PDF Techniques | Techniques for WCAG 2.0

PDF Techniques | Techniques for WCAG 2.0
Techniques for WCAG 2.0
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This document is no longer maintained. For the latest version, see
PDF Techniques for WCAG 2.0
This Web page lists PDF Techniques from
Techniques for WCAG 2.0: Techniques and Failures for Web Content Accessibility Guidelines 2.0
. Technology-specific techniques do not replace the general techniques: content developers should consider both general techniques and technology-specific techniques as they work toward conformance.
Publication of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0 success criteria and conformance requirements. Developers need to be aware of the limitations of specific technologies and provide content in a way that is accessible to people with disabilities.
For information about the techniques, see
Introduction to Techniques for WCAG 2.0
. For a list of techniques for other technologies, see the
Table of Contents
Table of Contents
Abstract
Status of This Document
PDF Technology Notes
PDF1: Applying text alternatives to images with the Alt entry in PDF documents
PDF2: Creating bookmarks in PDF documents
PDF3: Ensuring correct tab and reading order in PDF documents
PDF4: Hiding decorative images with the Artifact tag in PDF documents
PDF5: Indicating required form controls in PDF forms
PDF6: Using table elements for table markup in PDF Documents
PDF7: Performing OCR on a scanned PDF document to provide actual text
PDF8: Providing definitions for abbreviations via an E entry for a structure
element
PDF9: Providing headings by marking content with heading tags in PDF documents
PDF10: Providing labels for interactive form controls in PDF documents
PDF11: Providing links and link text using the Link annotation and the /Link structure element in PDF documents
PDF12: Providing name, role, value information for form fields in PDF documents
PDF13: Providing replacement text using the /Alt entry for links in PDF
documents
PDF14: Providing running headers and footers in PDF documents
PDF15: Providing submit buttons with the submit-form action in PDF forms
PDF16: Setting the default language using the /Lang entry in the document
catalog of a PDF document
PDF17: Specifying consistent page numbering for PDF documents
PDF18: Specifying the document title using the Title entry in the document
information dictionary of a PDF document
PDF19: Specifying the language for a passage or phrase with the Lang entry
in PDF documents
PDF20: Using Adobe Acrobat Pro's Table Editor to repair mistagged tables
PDF21: Using List tags for lists in PDF documents
PDF22: Indicating when user input falls outside the required format or
values in PDF forms
PDF23: Providing interactive form controls in PDF documents
PDF Technology Notes
Introduction
The Portable Document Format (PDF) is a file format for representing documents in a manner independent of the application software, hardware, and operating system used to create them, as well as of the output device on which they are to be displayed or printed. PDF files specify the appearance of pages in a document in a reliable, device-independent manner. The PDF specification was introduced by Adobe Systems in 1993 as a publicly available standard. In July 2008, PDF 1.7 became an ISO standard (ISO 32000-1)
[ISO32000]
Of note for accessibility is PDF/UA (Universal Accessibility) which became an ISO Standard in July 2012, and was updated in 2014 (ISO 14289-1:2014 (See
PDF/UA (ISO 14289-1:2014)
.) The scope of PDF/UA is not meant to be a techniques (how-to) specification, but rather a set of guidelines for creating more accessible PDF. The specification describes the required and prohibited components and the conditions governing their inclusion in or exclusion from a PDF file in order for the file to be available to the widest possible audience, including those with disabilities. The mechanisms for including the components in the PDF stream are left to the discretion of the individual developer, PDF generator, or PDF viewing agent. PDF/UA also specifies the rules governing the behavior for a conforming reader.
PDF Accessibility Support
PDF includes several features in support of accessibility of documents
to users with disabilities. The core of this support lies in the ability
to determine the logical order of content in a PDF document, independently
of the content's appearance or layout, through logical structure and
Tagged PDF. Applications can extract the content of
a document for presentation to users with disabilities by traversing
the structure hierarchy and presenting the contents of each node. For
this reason, producers of PDF files must ensure that all information
in a document is reachable by means of the structure hierarchy.
Logical Structure
PDF's logical structure features (introduced in PDF 1.3) provide a
mechanism for incorporating structural information about a document's
content into a PDF file. Such information might include, for example,
the organization of the document into chapters, headings, paragraphs
and sections or the identification of special elements such as figures,
tables, and footnotes. The logical structure features are extensible,
allowing applications that produce PDF files to choose what structural
information to include and how to represent it, while enabling PDF
consumers to navigate a file without knowing the producer's structural
conventions.
PDF logical structure shares basic features with standard document
markup languages such as HTML, SGML, and XML. A document's logical
structure is expressed as a hierarchy of structure elements, each represented
by a dictionary object. Like their counterparts in other markup languages,
PDF structure elements can have content and attributes. In PDF, rendered
document content takes over the role occupied by text in HTML, SGML,
and XML.
A PDF document's logical structure is stored separately from its visible
content, with pointers from each to the other. This separation allows
the ordering and nesting of logical elements to be entirely independent
of the order and location of graphics objects on the document's pages.
The logical structure of a document is described by a hierarchy of
objects called the structure hierarchy or structure tree. At the root
of the hierarchy is a dictionary object called the structure tree root,
located by means of the StructTreeRoot entry in the document catalog.
See Section 14.7.2, ("Structure Hierarchy") in
PDF
1.7 (ISO 32000-1)
: Table 322 shows the entries in the structure
tree root dictionary. The K entry specifies the immediate children
of the structure tree root, which are structure elements.
Tagged PDF
Tagged PDF (PDF 1.4) is a stylized use of PDF that builds on PDF's
logical structure framework. It defines a set of standard structure
types and attributes that allow page content (text, graphics, and images)
to be extracted and reused for other purposes. It is intended for use
by tools that perform the following types of operations:
Simple extraction of text and graphics for pasting into other applications.
Automatic reflow of text and associated graphics to fit a page
of a different size than was assumed for the original layout.
Processing text for such purposes as searching, indexing, and spell-checking.
Conversion to other common file formats (such as HTML, XML, and
RTF) with document structure and basic styling information preserved.
Making content accessible to people who rely on assistive technology.
PDF File Production and Accessibility
PDF files may be produced either directly by application programs or indirectly by conversion from other file formats or imaging models. In addition, tools exist for inspecting, checking, and repairing PDF files for accessibility. The following sections provide representative lists of applications and tools typically used for these functions.
These notes do not, and cannot, provide an exhaustive list, nor do they endorse particular applications and tools. Rather they provide a snapshot of tools in fairly wide use at the time the WCAG Working Group undertook to review and publish techniques for producing PDF documents. As with any software, application support for PDF accessibility will vary with different versions, with the formatting requirements of specific PDF documents, and with actual usage of the application. That is, the tools can be used properly to produce appropriate tags, etc..
In general, newer tools will provide greater support than earlier ones. The tools' vendors are the source of authoritative information about their support for PDF accessibility.
Generating PDF Files
Many applications can generate PDF files directly, and some can import
them as well. This direct approach is preferable, since it gives the
application access to the full capabilities of PDF, including the imaging
model and the interactive and document interchange features. Alternatively,
applications that do not generate PDF directly can produce PDF output
indirectly. There are two principal indirect methods:
The application describes its printable output by making calls
to an application programming interface (API) such as GDI in Microsoft®
Windows® or QuickDraw in the Apple Mac OS. A software component called
a printer driver intercepts these calls and interprets them to generate
output in PDF form.
The application produces printable output directly in some other
file format, such as PostScript, PCL, HPGL, or DVI, which is converted
to PDF by a separate translation program.
Although these indirect strategies are often the easiest way to obtain
PDF output from an existing application, the resulting PDF files may
not make the best use of the high-level PDF imaging model relied upon to expose the semantics of the document. This is
because the information embodied in the application's API calls or
in the intermediate output file often describes the desired results
at too low a level. Any higher-level information maintained by the
original application has been lost and is not available to the printer
driver or translator.
For example, since the printer driver or translator targets correct visual output, information about the semantics of the document may not be sent at all or may be ignored when creating the PDF output. As a result, headings may not be tagged as such, or link text may not be associated with its link object. Check with the vendor of any PDF authoring tool in order to understand how to use the tool in a way that produces the best tagged output.
PDF Authoring Tools that Provide Accessibility Support
Adobe Acrobat's PDFMaker - PDFMaker is part of Adobe Acrobat
which adds macros to many business applications such as Microsoft
Office, AutoCAD and Lotus Notes that support the conversion of content
from the original format to tagged PDF.
Adobe FrameMaker - Desktop publishing application from Adobe Systems
that directly exports tagged PDF and provides support for alternative
text descriptions.
Adobe InDesign - Page layout and desktop publishing application
from Adobe Systems that directly exports tagged PDF and provides
support for alternative text descriptions.
Adobe LiveCycle Designer - Windows-based forms design application
from Adobe Systems that directly exports tagged PDF interactive forms
and provides support for alternative text descriptions; can be invoked
standalone or from within Acrobat Pro.
LibreOffice - Open-source word processing software from The Document Foundation that can export tagged PDF.
Lotus Symphony Documents - Word-processing software from IBM that can export tagged PDF.
Microsoft® Word - Word processing application from Microsoft Corporation
that can export tagged PDF using the save as XPS or PDF utility.
OpenOffice.org Writer - Open source word-processing software from
Sun Microsystems Inc. that can export tagged PDF using the Export
as PDF utility.
CommonLook Office for Microsoft Office from Netcentric Technologies is an add-in to Microsoft® Word and PowerPoint that makes it possible to create tagged PDF documents. CommonLook Office provides tools to allow content authors to run accessibility tests in the Microsoft Word and PowerPoint environments and to remediate accessibility issues prior to conversion to PDF.
Xenos Axess™ for Accessible Statements - PDF software integrates with an organization's existing enterprise content management (ECM) infrastructure to capture high-volume print streams and automatically transform them into tagged PDFs.
WordPerfect® Office - Word-processing software from Corel that can be used to create, mark up, and share tagged PDF documents.
Microsoft Office 10 - a suite of desktop office applications that creates tagged PDF.
Note:
Care should be taken when choosing PDF creation tools from the many available, as some may not support creation of tagged PDF files.
Accessibility Checking and Repair
Adobe
Acrobat Pro
. Adobe Acrobat Pro is an application that creates and edits PDF files.
It has a number of tools for evaluating and repairing the accessibility
of PDF files, including access to the structure root through the
tags panel, the ability to directly manipulate the reading order
through the order panel, a built-in accessibility checker, and the
Touch Up Reading Order tool which provides a graphical mechanism for
assessing and repairing the accessibility of a PDF document.
Commonlook™
PDF
. Commonlook PDF. Commonlook PDF is a plug-in for Adobe Acrobat Pro from Netcentric Technologies. CommonLook PDF helps identify, report and correct the most common accessibility problems, including the proper tagging of images, tables, forms and other non-textual objects.
API Inspection Tools
aDesigner
- a disability simulator from the Eclipse Foundation that helps designers ensure that content is accessible and usable by visually impaired users.
inspect32
- part of the Microsoft Windows Software Development Kit (SDK) that allows developers and testers to examine the accessible properties of UI components.
PDDOMView
- part
of Acrobat_Accessibility_9.1.zip which contains files that can be
used by Windows clients of the accessibility interfaces described
in the Accessibility API Reference document.
UISpy
- part of the Microsoft Windows Software Development Kit (SDK) that allows developers and testers to view and interact with the user interface (UI) elements of an application.
User Agents
PDF User Agents with accessibility support include:
Adobe Acrobat Pro - PDF Authoring Tool, Editor, and Viewer from Adobe Systems which is compatible with MSAA devices on the Windows platform. Has a number of built in accessibility features including text to speech (Read Out Loud), high contrast display, reflow for large print display, auto scroll, accessibility full check, accessibility quick check, touch up reading order tool, and an accessibility setup assistant.
Adobe Reader – Freely distributed PDF Viewer from Adobe Systems which is compatible with MSAA devices on the Windows platform. Has a number of built in accessibility features including text to speech (Read Out Loud), high contrast display, reflow for large print display, auto scroll, accessibility quick check, and an accessibility setup assistant.
Kurzweil 3000™ - a comprehensive reading, writing and learning software solution from Kurzweil Educational Systems® which reads PDF files using text to speech facilities.
Adobe Reader and Acrobat Support for Accessibility APIs
Adobe provides methods to make the content of a PDF file available
to assistive technology such as screen readers:
On the Microsoft® Windows® operating system, Acrobat and Adobe
Reader export PDF content as Component Object Model (COM) objects. Accessibility applications
such as screen readers can interface with Acrobat or Adobe Reader
in two ways:
Through the Microsoft Active Accessibility (MSAA) interface,
using MSAA objects that Acrobat or Adobe Reader exports
Directly through exported COM objects that allow access to
the PDF document's internal structure, called the Document Object
Model (DOM).
On UNIX® platforms, Adobe Reader supports the Gnome accessibility
architecture. C-based Accessibility Toolkit (ATK) interfaces are
available.
The DOM and MSAA models are related, and developers can use either
or both. Acrobat issues notifications to accessibility clients about
interesting events occurring in the PDF file window and responds to
requests from such clients. Recent versions of Acrobat and Reader have
enhanced the support for accessibility interfaces:
MSAA interfaces are supported in Acrobat/Reader 5.0 and later.
In Acrobat/Reader 6.0 and later, information about the underlying
PDF structure is made available through direct COM objects that represent
the PDF DOM. The DOM accessibility interfaces provide somewhat more
extensive access.
In Acrobat/Reader 7.0 and later, ATK and expanded DOM support is
available.
The Linux®, Solaris™, AIX®, and HP-UX versions of Adobe Reader
implement C-based ATK interfaces, allowing screen readers, screen
magnifiers, and on-screen keyboards to query an Accessibility Technology
- Service Providers Interface (AT-SPI) registry for applications
that are accessible.
The DOM has been expanded to provide enhanced caret, selection,
and focus support, as well as the new interfaces IPDDomDocument,
ISelectText, and IPDDomNodeExt.
Assistive Technology Support
JAWS 12 for Windows - screen reader from Freedom Scientific. Support
for PDF started with JAWS version 4.
MAGic 11 - screen magnifier from Freedom Scientific
NVDA 2011.1 - NonVisual Desktop Access, open source screen reader
distributed by NV Access. Providing feedback via synthetic speech
and Braille, NVDA allows blind and vision-impaired people to access
and interact with the Windows operating system and many third party
applications.
Supernova Access Suite 12.02 – full screen reader offering magnification, speech, and Braille support from Dolphin. Support for PDF started with HAL version 5.
System Access To Go - screen reader from Serotek Corporation
VoiceOver - screen reader for Mac OS X v10.6 Snow Leopard
Window-Eyes 7.2 - screen reader from GW Micro. Window-Eyes was
the first screen reader to provide support for PDF files, in Window-Eyes
4.2.
ZoomText 9.1 - screen magnifier and screen reader from Ai Squared,
with support for Adobe Acrobat and Reader:
PDF documents can be read using both AppReader and DocReader
(without special settings)
PDF documents can be read in all Windows operating systems
(without special settings)
AppReader and DocReader start instantly in Adobe Reader
PDF documents can be read with greater accuracy and without
paging delays
PDF documents can be read in Internet Explorer (with the Adobe
Reader plug-in)
Special Adobe Reader settings are no longer needed to obtain
optimal reading
Related References
Adobe
Accessibility Resource Center
Adobe
Acrobat Accessibility Training Resources
Accessing
PDF Documents with Assistive Technology
PDF
Specification Archives
PDF
1.7 Reference: ISO approved copy of the ISO 32000-1
PDF
Accessibility API Reference - How AT developers can use Acrobat MSAA
and IPDDom interfaces to provide access to PDF content
PDF/UA
(ISO 14289-1:2012)
PDF/UA
Conformance Testing Model: The Matterhorn Protocol
WebAIM
PDF Accessibility
Create accessible PDFs
using Microsoft Office 10
PDF1: Applying text alternatives to images with the Alt entry in PDF documents
Applicability
Tagged PDF documents with images
This technique relates to:
Success Criterion 1.1.1 (Non-text Content)
How to Meet 1.1.1 (Non-text Content)
Understanding Success Criterion 1.1.1 (Non-text Content)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF1
. Also see
PDF Technology Notes
Description
The objective of this technique is to provide text alternatives for
images via an /Alt entry in the property list for a Tag. This is normally
accomplished using a tool for authoring PDF.
PDF documents may be enhanced by providing alternative descriptions
for images, formulas, and other items that do not translate naturally
into text. In fact, such text alternatives are required for accessibility:
alternate descriptions are human-readable text that can be vocalized
by text-to-speech technology for the benefit of users with vision disabilities.
When an image contains words that are important to understanding the
content, the text alternative should include those words. This will
allow the alternative to accurately represent the image. Note that
it does not necessarily describe the visual characteristics of the
image itself but must convey the same meaning as the image.
Examples
Example 1: Adding an /Alt entry to an image using Adobe Acrobat
9 Pro's TouchUp Object Tool
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Choose Tools > Advanced Editing > TouchUp Object Tool
Access the context menu for the image and choose Properties.
On the TouchUp Properties dialog, select the Tag tab.
On the Tag panel, type the text alternative in the Alternate Text
text box.
This example is shown in operation in the
working example of Adding an /Alt entry to an image
Example 2: Adding an /Alt entry to an image using Adobe Acrobat
9 Pro's TouchUp Reading Order Tool
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Choose Tools > Advanced Editing > TouchUp Reading Order
Tool
The TouchUp Reading Order dialog will be displayed.
Right-click on the image and choose Edit Alternate Text.
The Alternate Text dialog will be displayed.
Type the text alternative in the Alternate Text text box.
Example 3: Adding an /Alt entry to an image in PDF documents generated
using Microsoft Word
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Word 2000-2003
Right-click on the image and choose Format Picture
Select the Web tab
Type the alternative text into the text box provided and then
click OK.
Word 2007
Right-click on the image and choose Size
Select the Alt Text tab
Type the alternative text into the text box provided and then
click OK.
Example 4: Adding an /Alt entry to an image in PDF documents generated
using OpenOffice.org Writer 2.2
This example is shown with Open Office.org Writer. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Access the context menu for the image and choose Picture...
Select the Options tab
Type the alternative text into Alternate (Text Only) text box
and click OK.
Example 5: Adding a text alternative to an image in a PDF document
using an /Alt entry
The /Alt property used on an image of mountains with a moon and trees
typically would be used like this (typically accomplished by an authoring
tool):
/Figure <>
The image might also be represented by a tag with a different name.
A different name might be used because the tag name is written in
a language other than English or because a specific tool uses a different
name for some other reason. In this situation, it is also necessary
that the RoleMap contained within the StructTreeRoot for the PDF
document contain an entry which explicitly maps the name of the tag
used for the image with the standard structure type used in PDF documents
(in this case, Figure). If the RoleMap contains only an entry mapping
Shape tags to Figure tags, the rolemap information would appear as
follows:
/RoleMap << /Shape /Figure >>
In this case, the usage of the /Alt entry as follows would also
be correct:
/Shape <>
Note that the /Alt entry in property lists can be combined with
other entries.
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.9.4 (Replacement Text) in
PDF
1.7 (ISO 32000-1)
Acrobat
and Accessibility
PDF
Reference 1.6, 10.8.2 Alternate Descriptions
PDF and Accessibility
Related Techniques
G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content
Tests
Procedure
Verify the images which need equivalents have /Alt entries on
an enclosing tag by one of the following:
Read the PDF document with a screen reader, listening to hear
that the equivalent text is read when tabbing to the non-text
object (if it is tabbable) or hearing the alternative text read
when reading the content line-by-line.
Using a PDF editor, check that a text alternative is displayed for each
image.
Use a tool which is capable of showing the /Alt entry value,
such as aDesigner, to open the PDF document and view the GUI
summary to read the text alternatives for images.
Use a tool that exposes the document through the accessibility
API and verify that images have required text equivalents.
Expected Results
Check 1 is true for each image in the document which needs a text
equivalent.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF2: Creating bookmarks in PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 2.4.5 (Multiple Ways)
How to Meet 2.4.5 (Multiple Ways)
Understanding Success Criterion 2.4.5 (Multiple Ways)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF2
. Also see
PDF Technology Notes
Description
The intent of this technique is to make it possible for users to locate
content using bookmarks (
outline entries
in an Outline dictionary)
in long documents.
A person with cognitive disabilities may prefer a hierarchical outline
that provides an overview of the document rather than reading and traversing
through many pages. This is also a conventional means of navigating
a document that benefits all users.
Examples
Example 1: Converting a table of contents created with Microsoft
Word 2007 and creating bookmarks for Adobe Reader 9 and Acrobat 9 Pro
This example is shown with Microsoft Word and Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Create a table of contents at the beginning of the Word document.
Use Save as... > Adobe PDF to convert the Word document to
PDF, specifying both of the following:
Enable Accessibility and Reflow with Tagged Adobe PDF
Convert Word Headings into Bookmarks
The table-of-contents entries in the converted document will be linked
to the headings in the document.
In addition, the headings will appear as PDF Bookmarks in the left-hand
Navigation pane.
If the document provides a glossary and/or index, these sections
should have headings that appear in the table of contents (and thus
as bookmarks in the Navigation pane). The table of contents also
should be marked up with a heading so it is bookmarked as well.
If this markup has not been done in the authoring tool, Adobe Acrobat
Pro can be used to provide the tags. See
PDF9: Providing headings by marking content with heading tags in PDF documents
if
you need to modify converted headings or add new ones.
This example is shown in operation in the
working example of creating bookmarks with Word 2007
Example 2: Converting a table of contents created with OpenOffice.org
Writer 2.2 and creating bookmarks for Adobe Reader 9 and Acrobat 9
Pro
This example is shown with OpenOffice.org Writer and Adobe Acrobat Pro and Reader. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Create a table of contents at the beginning of the OpenOffice.org
Writer document:
Insert > Indexes and Tables... > Indexes and Tables > Insert
Index/Table
Use File > Export as PDF... to convert the document to PDF,
specifying Tagged PDF in the Options dialog.
The table-of-contents entries in the converted document will be linked
to the headings in the document, and will appear as PDF Bookmarks in
the left-hand Navigation pane. The OpenOffice.org Table of Contents
and Bookmarks look the same as they appeared in Example 1.
This example is shown in operation in the
working example of creating bookmarks with OpenOffice Writer
Example 3: Adding bookmarks using Adobe Acrobat 9 Pro after conversion
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
After conversion to tagged PDF, you may decide to add bookmarks that
were not automatically generated. Like the converted bookmarks, tagged
bookmarks use the underlying structural information in the document.
In the Bookmarks panel, choose the options menu, then choose New
Bookmarks From Structure...
From the Structure Elements dialog, select the elements you want
specified as tagged bookmarks.
The image below shows the Bookmarks options menu.
The next image shows the selection of links in the document for bookmarking.
The tagged bookmarks are nested under a new, untitled bookmark. Access
the context menu for the new bookmark and select the Rename option
to rename the new bookmark, as shown in the following image.
This example is shown in operation in the
working example of creating bookmarks with Acrobat Pro
Example 4: Creating bookmarks with the outline hierarchy
The following code fragment illustrates part of an outline hierarchy
used to create bookmarks This is typically accomplished by an authoring
tool.
121 0 obj
<< /Type /Outlines
/First 22 0 R
/Last 29 0 R
/Count 6
>>
endobj
22 0 obj
<< /Title (Applying Guerrilla Tactics to Usability Testing by People with Disabilities)
/Parent 21 0 R
/Next 29 0 R
/First 25 0 R
/Last 28 0 R
/Count 4
/Dest [3 0 R /XYZ 0 792 0]
>>
endobj
25 0 obj
<< /Title (Getting started)
/Parent 22 0 R
/Next 26 0 R
/Dest [3 0 R /XYZ null 701 null]
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 12.3.3 (Document Outline) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
G64: Providing a Table of Contents
Tests
Procedure
Check that the Bookmarks panel displays bookmarks.
Check that the bookmarks link to the correct sections in the document.
Expected Results
Check #1 and Check #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF3: Ensuring correct tab and reading order in PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 1.3.2 (Meaningful Sequence)
How to Meet 1.3.2 (Meaningful Sequence)
Understanding Success Criterion 1.3.2 (Meaningful Sequence)
Success Criterion 2.1.1 (Keyboard)
How to Meet 2.1.1 (Keyboard)
Understanding Success Criterion 2.1.1 (Keyboard)
Success Criterion 2.1.3 (Keyboard (No Exception))
How to Meet 2.1.3 (Keyboard (No Exception))
Understanding Success Criterion 2.1.3 (Keyboard (No Exception))
Success Criterion 2.4.3 (Focus Order)
How to Meet 2.4.3 (Focus Order)
Understanding Success Criterion 2.4.3 (Focus Order)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF3
. Also see
PDF Technology Notes
Description
The intent of this technique is to ensure that users can navigate
through content in a logical order that is consistent with the meaning
of the content. Correct tab and reading order is typically accomplished
using a tool for authoring PDF.
For sighted users, the logical order of PDF content is also the visual
order on the screen. For keyboard and assistive technology users, the
tab order through content, including interactive elements (form fields
and links), determines the order in which these users can navigate
the content. The tab order must reflect the logical order of the document.
Logical structure is created when a document is saved as tagged PDF.
The reading order of a PDF document is determined primarily by the tag order of document elements, including interactive elements, but the order of content within individual tags is determined by the PDF document’s content tree structure.
If the reading order is not correct, keyboard and assistive technology
users may not be able to understand the content. For example, some
documents use multiple columns, and the reading order is clear visually
to sighted users as flowing from the top to the bottom of the first
column, then to the top of the next column. But if the document is
not properly tagged, a screen reader may read the document from top
to bottom, across both columns, interpreting them as one column.
The simplest way to ensure correct reading order is to structure the
document correctly in the authoring tool used to create the document,
before conversion to tagged PDF. Note, however, that pages with complex
layouts with graphics, tables, footnotes, side-bars, form fields, and
other elements may not convert to tagged PDF in the correct reading
order. These inconsistencies must then be corrected with repair tools
such as Acrobat Pro.
When a PDF document containing form fields has a correct reading order,
all form fields are contained in the tab order in the appropriate order,
and in the correct order relative to other content in the PDF. Common
tab-order errors include:
Form fields missing from the tagged content.
Form fields in the wrong location in the PDF content; e.g., at
the end of non-interactive content.
Examples
Example 1: Creating a 2-column document using Microsoft Word 2007
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Multi-column documents created using Word's Page Layout > Columns...
tool typically are in the correct reading order when converted to tagged
PDF. The image below shows Word's Columns tool.
This example is shown in operation in the
working example of 2-column document using Word 2007 (Word file)
and
working example of 2-column document using Word 2007 (PDF file)
Example 2: Creating a 2-column document using OpenOffice.org Writer
2.2
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Multi-column documents created using OpenOffice.org Writer's Format > Columns...
tool typically are in the correct reading order when converted to tagged
PDF. The image below shows Writer's Columns tool.
This example is shown in operation in the
working example of 2-column document using OpenOffice Writer (OpenOffice file)
and
working example of 2-column document using OpenOffice Writer (PDF file)
Example 3: Setting the tab order for one or more pages using Adobe
Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In a tagged PDF document:
Open the Pages panel by either:
Clicking the Pages icon
Or selecting View > Navigation Panels > Pages
Select one or more page thumbnails.
Access the context menu for the selected thumbnail(s) and select
Page Properties...
Select the Tab Order tab in the Page Properties dialog.
If needed, select a tab order option:
Option
Description
Use Row Order
Tabs from the upper left field, moving first left to right
and then down, one table row at a time.
Use Column Order
Tabs from the upper left field, moving first from top to
bottom and then across from left to right, one table column
at a time.
Use Document Structure
For tagged documents, moves in the tag order specified by
the authoring application.
Note:
This is usually the correct reading
order and will be selected by default for tagged documents.
Unspecified
If the document was created using an earlier version of
Acrobat Pro, the tab order is Unspecified by default. With
this setting, form fields are tabbed through first, followed
by links and then comments ordered by row. This may not be
correct reading order.
This example is shown in operation in the
working example of setting the tab order (Word file)
and
working example of setting the tab order (PDF file)
Example 4: Repairing the reading order using the Tags panel in Adobe
Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in PDF Authoring Tools that Provide Accessibility Support
(http://trace.wisc.edu/wcag_wiki/index.php?title=PDF_Technology_Notes).
To correct the reading order in Example 5, use the Tags panel, and either
Drag-and-drop the
H1
tag to precede the required-field text
(tagged
H2
), or
Cut-and-paste the
H2
tag to follow the
H1
tag.
In the following image, the reading order is correct for the text and
header. That is, the content elements
H1
and
H2
have been switched
into the correct reading order.
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8 (Tagged PDF) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Making PDF documents accessible with Adobe Acrobat Pro
Related Techniques
G57: Ordering the content in a meaningful sequence
G59: Placing the interactive elements in an order that follows sequences and relationships within the content
G202: Ensuring keyboard control for all functionality
Tests
Procedure
Verify that the content is in the correct reading order by one
of the following:
Read the PDF document with a screen reader or a tool that reads aloud, listening to hear that each element is read in
the correct order.
Use a tool that exposes the document through the accessibility
API, and verify that the reading order is correct.
Verify that the tab order is correct for focusable content by
one of the following:
Use the tab key to traverse the focus order in the document.
Use a tool that is capable of showing the page object entry
that specifies the tab order setting to open the PDF document
and view the setting.
Expected Results
#1 and Check #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF4: Hiding decorative images with the Artifact tag in PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 1.1.1 (Non-text Content)
How to Meet 1.1.1 (Non-text Content)
Understanding Success Criterion 1.1.1 (Non-text Content)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF4
. Also see
PDF Technology Notes
Description
The purpose of this technique is to show how purely decorative images
in PDF documents can be marked so that they can be ignored by Assistive
Technology by using the /Artifact tag. This is typically accomplished
by using a tool for authoring PDF.
In PDF, artifacts are generally graphics objects or other markings
that are not part of the authored content. Examples of artifacts include
page header or footer information, lines or other graphics separating
sections of the page, or decorative images.
Examples
Example 1: Marking a background image as an artifact using Adobe
Acrobat 9 Pro's TouchUp Reading Order Tool
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
The TouchUp Reading Order Tool can be used to mark an image as "Background," which
removes it from the document tag structure.
Open the TouchUp Reading Order Tool in Acrobat Pro: Advanced > Accessibility > TouchUp
Reading Order
Select the decorative image in the document
In the TouchUp Reading Order Tool, click the Background button
to remove the selected image from the tag structure
The screenshot below illustrates this example.
This example is shown in operation in the
working example of creating a decorative image (Word file)
and
working example of marking a background image as an artifact (PDF file)
Example 2: Marking an image as an artifact in a PDF document using
an /Artifact tag or property list
The PDF specification allows images to be marked as "artifacts" as
defined in Section 14.8.2.2 (Real Content and Artifacts) in
PDF
1.7 (ISO 32000-1)
. An artifact is explicitly distinguished from
real content by enclosing it in a marked-content sequence with the
/Artifact tag.
/Artifact
BMC ... EMC
or
/Artifact propertyList
BDC ... EMC
The first is used to identify a generic artifact; the second is
used for artifacts that have an associated property list. Note, to
aid in text reflow, artifacts should be defined with property lists
whenever possible. Artifacts lacking a specified bounding box are
likely to be discarded during reflow.
Property list entries for artifacts include Type, BBox, Attached,
and Subtype.
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.2.2 (Real Content and Artifacts) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Tests
Procedure
For an image that is purely decorative, use one of the following
to verify that it is marked as an artifact:
Read the PDF document with a screen reader, listening to hear
that the decorative image is not announced when
reading the content line-by-line.
Using a PDF editor, make sure the decorative image is marked as an artifact.
Reflow the document and make sure the
decorative image does not appear on the page.
Use a tool that is capable of showing the /Artifact entry
or property list, such as aDesigner, to open the PDF document
and verify that decorative images are marked as artifacts.
Use a tool
that exposes the document through the accessibility API and verify that the
decorative image is not exposed through the API.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF5: Indicating required form controls in PDF forms
Applicability
Tagged PDF documents with forms
This technique relates to:
Success Criterion 3.3.1 (Error Identification)
How to Meet 3.3.1 (Error Identification)
Understanding Success Criterion 3.3.1 (Error Identification)
Success Criterion 3.3.2 (Labels or Instructions)
How to Meet 3.3.2 (Labels or Instructions)
Understanding Success Criterion 3.3.2 (Labels or Instructions)
Note:
This technique must be combined with other techniques to meet
SC 3.3.2
. See
Understanding SC 3.3.2
for details.
Success Criterion 3.3.3 (Error Suggestion)
How to Meet 3.3.3 (Error Suggestion)
Understanding Success Criterion 3.3.3 (Error Suggestion)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF5
. Also see
PDF Technology Notes
Description
The objective of this technique is to notify the user when a field
that must be completed has not been completed in a PDF form. Required
fields are implemented using the /Ff entry in the form field's dictionary
(see Table 220 in Section 12.7 (Interactive Forms) of
PDF
1.7 (ISO 32000-1)
. This is normally accomplished using a tool for
authoring PDF.
If errors are found, an alert dialog describes the nature of the error
in text. This may be accomplished through scripting created by the
author (see, for example,
SCR18:
Providing client-side validation and alert
). User agents, such
as Adobe Acrobat Pro and LiveCycle, can provide automatic alerts (as
described in the examples below).
Note
: once the user dismisses the alert dialog, it
may be helpful if the script positions the keyboard focus on the field
where the error occurred, although some users may expect the focus
to remain on the last control focused prior to the alert appearing.
Authors should exercise care to ensure that any movement of the focus
will be expected. For example, if the alert announces a missing required
phone number, positioning the focus on the phone number field when
the alert is dismissed can be regarded as helpful and expected. In
some cases, however, this may not be possible. If multiple input errors
occur on the page, another approach must be taken to error reporting.
(See, for example, the
Adobe scripting resources.
Ensuring that users are aware an error has occurred, can determine
what is wrong, and can correct it are keys to software usability and
accessibility. Meeting this objective helps ensure that all users can
complete transactions with ease and confidence.
Labels for required form controls
It is also important that users are aware that an error
may
occur.
You can incorporate this information in labels; for example, "Date
(required)" or the use of a red asterisk to indicate required
fields. (Make sure that a legend appears on each form with required
fields, e.g., "* = required field".) See
PDF10: Providing labels for interactive form controls in PDF documents
Examples
Example 1: Creating a required field in a PDF form using Adobe Acrobat
9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Access the context menu of the field and select the Properties
dialog.
If the field is required, check the Required box. This checkbox
forces the user to fill in the selected form field. If the user attempts
to submit the form while a required field is blank, an error message
appears and the empty required form field is highlighted.
This example is shown in operation in the
working example of creating a required field in Acrobat
Example 2: Creating a required field in a PDF form using Adobe LiveCycle
Designer ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Access the context menu of the form control, select Palettes,
and select Object.
Select "User entered - Required" from the Type pulldown.
Enter an error message in the "Empty Message" field.
This message appears when a user tries to submit the form without
entering a value in the required field.
If the user attempts to submit the form with a required field left
blank, the Empty Message text appears and the empty required field
is highlighted.
The image below shows the Adobe LiveCycle Object palette with the
required selection.
You can also add explicit text to the form label to indicate required
fields (e.g., "(Required)").
This example is shown in operation in the
working example of creating a required field in LiveCycle Designer
Example 3: Adding a required text field in a PDF form using the /Tx
field type and Ff flag
The following code fragment illustrates code that is typical for the
object definitions for a typical text field. Note that the text field
is required, using the Ff flag. This is typically accomplished by an
authoring tool.
<< /AP -dict-
/DA /Helv 0 Tf 0 g
/DR -dict-
/F 0x4
/FT Tx % FT key set to Tx for Text Field
/Ff 0x2 % Ff integer 0x2 value indicates required
/P -dict-
/Rect -array-
/StructParent 0x1
/Subtype Widget
/T First % Partial field name First
/TU First name (required) % TU tool tip value serves as short description
/Type Annot
/V Pat Jones
>>
...

BT
/P <>BDC
/CS0 cs 0 scn
/TT0 1 Tf
-0.001 Tc 0.003 Tw 11.04 0 0 11.04 72 709.56 Tm
[(P)-6(le)-3(as)10(e)-3( )11(P)-6(rin)2(t)-3( Y)8(o)-7(u)2(r N)4(a)11(m)-6(e)]TJ
0 Tc 0 Tw 9.533 0 Td
( )Tj
-0.004 Tc 0.004 Tw 0.217 0 Td
[(\()-5(R)-4(e)5(q)-1(u)-1(i)-3(r)-3(e)-6(d)-1(\))]TJ
EMC
/P <>BDC
0 Tc 0 Tw 4.283 0 Td
[( )-2( )]TJ
EMC
/ArtifactSpan <>BDC
0.002 Tc -0.002 Tw 0.456 0 Td
[(__)11(___)11(___)11(___)11(___)11(_)11(____)11(___)11(___)11(__)]TJ
0 Tc 0 Tw 13.391 0 Td
( )Tj
EMC
ET

Resources
Resources are for information purposes only, no endorsement implied.
Section 12.7 (Interactive Forms) in
PDF
1.7 (ISO 32000-1)
Adobe
XML Forms Architecture (XFA)
PDF and Accessibility
Related Techniques
G83: Providing text descriptions to identify required fields that were not completed
H90: Indicating required form controls using label or legend
SCR18: Providing client-side validation and alert
PDF23: Providing interactive form controls in PDF documents
PDF10: Providing labels for interactive form controls in PDF documents
PDF22: Indicating when user input falls outside the required format or
values in PDF forms
Tests
Procedure
For each form field that is required, verify that validation information
and instructions are provided by applying the following:
Check that the required status is indicated in the form control's
label.
Leave the field blank and submit the form. Check that an alert
describing the error is provided.
Use a tool that exposes the document through the accessibility
API, and verify that the required property is indicated.
Expected Results
#1, #2, and #3 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF6: Using table elements for table markup in PDF Documents
Applicability
Tagged PDF documents with tables
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF6
. Also see
PDF Technology Notes
Description
The purpose of this technique is to show how tables in PDF documents
can be marked up so that they are recognized by assistive technology.
This is typically accomplished by using a tool for authoring PDF.
Tabular information must be presented in a way that preserves relationships
within the information even when users cannot see the table or the
presentation format is changed. Information is considered tabular when
logical relationships among text, numbers, images, or other data exist
in two dimensions (vertical and horizontal). These relationships are
represented in columns and rows, and the columns and rows must be recognizable
in order for the logical relationships to be perceived.
Tagged tables can be created using the Add Tags to Document feature
in Adobe Acrobat, using the Object Library in Adobe LiveCycle, or converting
tables to PDF from a third-party application, such as Microsoft Word.
However, the resulting tables may not be tagged correctly and you should
ensure that table tagging issues are resolved.
Within PDF documents, a table uses the following structure types for
table elements:
A table element (
Table
).
One or more table row elements(
TR
) which define each
row of table cells as immediate children of the
Table
element.
One or more table header elements (
TH
) or table data
elements (
TD
) as the immediate children of each table row
element.
Cells that span two or more rows or columns should use the
RowSpan
or
ColSpan
attribute.
For tables that contain blank cells, you may need to add empty
TD
cells
so that each row or column has the same number of cells.
Examples
Example 1: Creating tables in Microsoft Word 2007 that have correctly
tagged headings when converted to PDF
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Access the table header row's context menu and select Table Properties...
Select the Row tab.
Check "Repeat as header at the top of each page" as
shown in the following image.
This example is shown in operation in the
working example of tagged table headings in Word 2007
Note:
Microsoft Word can only mark up cells as column headings, not as row headings. Only the first row can be marked as heading for all table columns. When the table has row headings or a more complex heading structure, this mark-up must be added in a PDF editor such as Acrobat Pro.
Example 2: Creating tables in OpenOffice.org Writer 2.2 that have
correctly tagged headings when converted to PDF
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Access the table's context menu and select Table...
Select the Table Format tab.
Check Repeat Heading and select "1" in the First Rows
listbox as shown in the following image.
This example is shown in operation in the
working example of tagged table headings in OpenOffice Writer
Note:
OpenOffice.org Writer can only mark up cells as column headings, not as row headings. Only the first row can be marked as heading for all table columns. When the table has row headings or a more complex heading structure, this mark-up must be added in a PDF editor such as Acrobat Pro.
Example 3: Modifying table tags using the Tags tab in Adobe Acrobat
9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
To check that a converted document with tables has correct table tagging:
In the View menu, select Navigation Panel, then select Tags.
Note that in this case, the table headers were not formatted as illustrated
in Examples 1 and 2, and are marked as data cells (
TD
). To
change these to
TH
tags:
On the Tags tab, open the table row that contains the header cells,
as shown on the image above.
Select on the first data cell and select Properties...
On the Tags tab in the Properties dialog, use the Type dropdown
to change Table Data Cell to Table Header Cell.
Repeat for all the table header cells in the first table row.
This example is shown in operation in the
working example of tagged table headings in Acrobat
Example 4: Marking up a table using table structure elements
The following code fragment illustrates code that is typical for a
simple table (header row and data row) such as shown in Examples 1-3:
95 0 obj %Structure element for a table
<<
/A 39 0 R
/K[96 0 R 101 0 R 106 0 R 111 0 R]
/P 93 0 R
/S/Table %standard structure type is table
>>
endobj
96 0 obj %Structure element for a table row
<<
/K[97 0 R 98 0 R 99 0 R 100 0 R]
/P 95 0 R
/S/TR %standard structure type is table row
>>
endobj
97 0 obj %Structure element for a table header
</K 1
/P 96 0 R
/S/TH %standard structure type is table head
/Pg 8 0 R
>>
endobj
104 0 obj %Structure element for table data (cell contents)
<<
/A 29 0 R
/K 7
/P 101 0 R
/S/TD %standard structure type is table data
/Pg 8 0 R
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.4.3.4 (Table Elements) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
H51: Using table markup to present tabular information
PDF20: Using Adobe Acrobat Pro's Table Editor to repair mistagged tables
Tests
Procedure
For each table, confirm one of the following:
Read the PDF document with a screen reader, listening to hear
that the tabular information is presented in a way that preserves
logical relationships among the table header and data cells.
Using a PDF editor, verify that the appropriate
TR
TH
and
TD
tags are in the proper reading order and hierarchy
in the table tree.
Use a tool which is capable of showing the table elements
to open the PDF document, view the table structure, and verify
that it contains the appropriate TR, TH, and TD structures.
Use a tool that exposes the document through the accessibility
API, and verify that the table structure contains the appropriate
TR, TH, and TD structures, and that they are in the proper reading
order and hierarchy.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF7: Performing OCR on a scanned PDF document to provide actual text
Applicability
Scanned PDF documents
This technique relates to:
Success Criterion 1.4.5 (Images of Text)
How to Meet 1.4.5 (Images of Text)
Understanding Success Criterion 1.4.5 (Images of Text)
Success Criterion 1.4.9 (Images of Text (No Exception))
How to Meet 1.4.9 (Images of Text (No Exception))
Understanding Success Criterion 1.4.9 (Images of Text (No Exception))
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF7
. Also see
PDF Technology Notes
Description
The intent of this technique is to ensure that visually rendered text
is presented in such a manner that it can be perceived without its
visual presentation interfering with its readability.
A document that consists of scanned images of text is inherently inaccessible
because the content of the document is images, not searchable text.
Assistive technologies cannot read or extract the words; users cannot
select, edit, resize, or reflow text nor can they change text and background
colors; and authors cannot manipulate the PDF for accessibility.
For these reasons, authors should use actual text rather than images
of text, using an authoring tool such as Microsoft Word or Oracle Open
Office to author and convert content to PDF.
If authors do not have access to the source file and authoring tool,
scanned images of text can be converted to PDF using optical character
recognition (OCR). Adobe Acrobat Pro can then be used to create accessible
text.
Examples
Example 1: Generating actual text rather than images of text using
Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
This example uses a simple one-page scanned image of text. To ensure
that actual text is stored in the document, perform the following steps:
Scan the document using as high a resolution as possible to improve
the OCR performance.
Load the scanned document in Acrobat Acrobat Pro. Select Document > OCR
Text Recognition > Recognize Text Using OCR...
In the next dialog, select the All Pages radio button under Pages
(or Current Page if you are converting only one page), and then select
OK.
Under the Settings list, select Edit. In the next dialog, select
Formatted Text and Graphics in the PDF Output Style drop-down list.
This is important for ensuring accessibility.
Depending on the resolution and how clear the text was, OCR converts
images of words and characters to actual text. Text that Acrobat
Pro does not recognize is listed as an "OCR suspect," or
text element that Acrobat suspects was not recognized correctly.
To fix the suspects, choose Document > OCR Text Recognition > Find
First OCR Suspect. Acrobat Pro presents each suspect one at a time,
which can be corrected using Acrobat Pro touchup tools.
Run Advanced > Accessibility > Add Tags to Document
Test for accessibility: Advanced > Accessibility > Full
Check...
Note:
Alternatively, you can use Document > OCR
Text Recognition > Find All OCR Suspects to display all OCR suspects
at the same time for faster editing.
The following image shows a scanned one-page document in Adobe Acrobat
Pro.
The next image shows the converted content after adding tags to the
document. It will probably be necessary to use the TouchUp Reading
Order tool and the Tags panel to tag the content properly for the intended
final document. For this example, the image of the spiral book binding
was tagged in the conversion. The TouchUp Reading Order tool was used
to hide the image as a background (decorative) image (see
PDF4: Hiding decorative images with the Artifact tag in PDF documents
). The recipe
titles were tagged as first level headers.
Note: Acrobat Pro may automatically add tags when the file is run
through OCR.
This example is shown in operation in the
working example of generating actual text
and the
result of performing OCR
Resources
Resources are for information purposes only, no endorsement implied.
PDF and Accessibility
Related Techniques
G140: Separating information and structure from presentation to enable different presentations
Tests
Procedure
For each page converted to text using OCR, ensure that the resulting
PDF has been converted correctly, using one of the following ways:
Read the PDF document with a screen reader or a tool that reads aloud, listening to hear that all text is read correctly
and in the correct reading order.
Save the document as text and check that the converted text
is complete and in the correct reading order.
Use a tool that is capable of showing the converted content
to open the PDF document and verify that all text was converted
and is in the correct reading order.
Use a tool that exposes the document through the accessibility
API and verify that all text was converted and is in the correct
reading order.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF8: Providing definitions for abbreviations via an E entry for a structure
element
Applicability
Tagged PDF documents containing abbreviations or acronyms
This technique relates to:
Success Criterion 3.1.4 (Abbreviations)
How to Meet 3.1.4 (Abbreviations)
Understanding Success Criterion 3.1.4 (Abbreviations)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF8
. Also see
PDF Technology Notes
Description
The objective of this technique is to provide an expansion or definition
of an abbreviation for the first occurrence of the abbreviation. For
example, a reference to an abbreviation, such as "WCAG," should
be available as "Web Content Accessibility Guidelines (WCAG)" on
its first occurrence in a document.
This is done by setting expansion text using an /E entry for a structure
element, and is normally accomplished using a tool for authoring PDF.
A Span structure element is typically used to tag the abbreviation,
but the /E entry is valid with any structure element.
This technique is applicable for any abbreviation, including acronyms
and initialisms. Note that on the first occurrence of the abbreviation,
both the abbreviation and the expansion text must be provided. This
will aid recognition of later use of the abbreviation.
PDF documents may be enhanced by providing expansions for abbreviations.
In fact, such expansions are required for accessibility to ensure understanding
by people who have difficulty decoding words; rely on screen magnification
(which may obscure context); have limited memory; or who have difficulty
using context to aid understanding.
Examples
Example 1: Adding an /E entry to an abbreviation using Adobe Acrobat
9 Pro's Tags panel
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In a tagged PDF document:
Select the Tags panel, using Views > Navigation Panes > Tags
Select the first instance of the abbreviated text that needs to be expanded. If the selected text is part of a larger tag, access the Tags panel options menu, select Create Tag from Selection, and create a new Span tag. In this example, the text "WCAG2" (within the LBody tag) has been enclosed in a Span tag.
In the Tags panel, access the context menu for the spanned text
and select Properties... to open the TouchUp Properties dialog for
the Span tag.
On the Content tab of the TouchUp Properties dialog, enter the
expansion text, followed by the originally selected text.
The following image illustrates this technique:
This example is shown in operation in the
working example of Providing definitions for Abbreviations (Word document)
working example of Providing definitions for Abbreviations (OpenOffice document)
, and
working example of Providing definitions for Abbreviations (PDF document)
Example 2: Using a /Span structure element with an /E entry to define
an abbreviation
The following code fragment illustrates code that is typical for using
the /Span structure element to define an abbreviation.
This example uses the sentence "Sugar is commonly sold in 5 lb
bags." The abbreviation "lb" is tagged as a /Span structure
element with an /E entry (typically accomplished by an authoring tool).
1 0 obj % structure element
<< /Type /StructElemen
/S /Span % element type
/P ... % Parent in structure hierarchy
/K << /Type /MCR
/Page 2 0 R % Page containing marked-content sequence
/MCID 0 % Marked content identifier for "lb"
>>
/E (pound, lb)
>>
endobj
Example 3: Using a /TH structure element with an /E entry to define
an abbreviation
As noted in the Description, the /E entry is valid with any structure
element.
The following code fragment illustrates code that is typical for using
an /E entry to define an abbreviation.
A table that contains columns for each month uses abbreviations as
the values of column headers. The expansion for each abbreviation is
provided as the /E entry of the /TH structure element (typically accomplished
by an authoring tool).
1 0 obj % structure element
<< /Type /StructElemen
/S /TH % element type
/P ... % Parent in structure hierarchy
/K << /Type /MCR
/Page 2 0 R % Page containing marked-content sequence
/MCID 0 % Marked content identifier for "Dec"
>>
/E (December, Dec)
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.9.5 (Expansion of Abbreviations and Acronyms) in
PDF
1.7 (ISO 32000-1)
Microsoft
Inspect.exe tool
PDF and Accessibility
Related Techniques
G102: Providing the expansion or explanation of an abbreviation
G55: Linking to definitions
G62: Providing a glossary
G70: Providing a function to search an online dictionary
G97: Providing the first use of an abbreviation immediately before or after the expanded form
Tests
Procedure
Verify that the first occurrence of abbreviations that require
expansion text have /E entries on an enclosing tag by one of the
following and that both the abbreviation and the expansion text are
provided:
In Windows, use Microsoft's Inspect.exe tool, or some other
tool that allows inspection of the MSAA interface, to locate
the text of the abbreviation in the document tree and ensure
that the value of the abbreviation is in the expansion text.
In a PDF editor, locate the tag
for the text that is the abbreviation, and check that an expansion
or definition is provided for each abbreviation in the Expansion
Text field in the corresponding tag's properties.
Read the PDF document with a screen reader, listening to hear
that on the first occurrence, the abbreviation and expansion
are read when the screen reader reads the content line-by-line.
Use a tool that is capable of showing the /E entry value,
such as aDesigner to open the PDF document and view the GUI summary
to read the text expansions for abbreviations.
Use a tool that exposes the document through the accessibility
API and verify that the text expansion of the abbreviation is
properly implemented.
Expected Results
Check #1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF9: Providing headings by marking content with heading tags in PDF documents
Applicability
Tagged PDF documents with headings
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
Success Criterion 2.4.1 (Bypass Blocks)
How to Meet 2.4.1 (Bypass Blocks)
Understanding Success Criterion 2.4.1 (Bypass Blocks)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF9
. Also see
PDF Technology Notes
Description
The purpose of this technique is to show how headings in PDF documents
can be marked so that they are recognized by assistive technologies. Headings are marked up using the heading elements (H, H1, H2, ... H6) in the structure tree.
This is typically accomplished by using a tool for authoring PDF.
Heading markup can be used:
to indicate start of main content
to mark up section headings within the main content area
to demarcate different navigational sections, such as top or main
navigation, left or secondary navigation, and footer navigation
to mark up images (containing text) which have the appearance
of headings visually.
Because headings indicate the start of important sections of content,
it is possible for assistive technology users to access the list of
headings and to jump directly to the appropriate heading and begin
reading the content. This ability to "skim" the content through
the headings and go directly to content of interest significantly speeds
interaction for users who would otherwise access the content slowly.
Examples
Example 1: Adding or modifying tagged headings in PDF documents
with Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Using the Touchup Reading Order tool
One method of adding headings to PDF documents uses the Touchup Reading
Order tool:
Open the PDF document in Adobe Acrobat Pro
Select Advanced > Accessibility > TouchUp Reading Order...
Click the Show Order Panel button on the TouchUp Reading Order
panel
View the tags in the Show Order panel.
The following image shows a PDF document opened in Adobe Acrobat Pro.
The Tags panel is open, showing heading text "Cooking techniques" tagged
as H1 and "Cooking with oil" tagged as H2. The text "Cooking
with butter" should be tagged as H2 but is not.
To correct the H2 heading, use the TouchUp Reading Order panel as
follows:
Left click and drag a selection box over the content you want to
tag.
Select the Heading 2 tag from the TouchUp Reading Order panel.
The following image shows the PDF document opened in Adobe Acrobat
Pro. The TouchUp Reading Order panel is visible. A selection box appears
around the text "Cooking with butter," and Heading 2 on the
panel is selected.
Finally, click the Show Order Panel button on the TouchUp Reading Order
panel.
The following image shows the PDF document opened in Adobe Acrobat
Pro. The Tags panel is visible, showing that the text "Cooking
with butter" is now tagged as H2.
Using the Order and Tags panels
You can also add or change headings as follows:
Bring up the Order panel.
Access the context menu for the text to be changed or added as
a heading.
Select the correct heading tag for the text.
The following screenshot shows Order panel and the context menu for
the text "Cooking with butter." "Tag as heading 2" is
selected in the context menu.
You can then check that the correct heading is applied by opening
the Tags panel, as shown in the following screenshot.
This example is shown in operation in the
working example of adding tagged headings (Word file)
and
working example of adding tagged headings (PDF file)
Example 2: Creating documents in Microsoft Word that have correctly
tagged headings when converted to PDF
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Use Styles to create heading formats: Heading 1, Heading 2, Heading
3, etc. Make styles progress in a logical manner; e.g., a Heading 2
should come after a Heading 1.
In Microsoft Word 2003
Select the "Format > Styles and Formatting" menu
item to reveal the styles and formatting task pane.
Use the Heading 1 to Heading 6 styles provided in the "Styles
and Formatting" panel.
In Microsoft Word 2007/2010
Select the Home Ribbon in Word 2007/2010 and select the appropriate
heading (Heading 1 to Heading 6) from the Styles group.
Example 3: Creating documents in OpenOffice.org Writer 2.2 that have
correctly tagged headings when converted to PDF
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Use Styles to create heading formats: Heading 1, Heading 2, Heading
3, etc. Make styles progress in a logical manner; e.g., a Heading 2
should come after a Heading 1.
Export to PDF as follows:
From the File menu, select Export as PDF...
The first time you export as PDF, an Options Dialog appears.
Select Tagged PDF, then select Export.
Example 4: Marking up headings using /Hn elements
Headings within PDF documents can be marked up using /H
elements elements
in the structure tree, where
is numeral 1 through 6 (for
example /H1, /H2, etc.).
The following code fragment illustrates code that is typical for using
the /H
elements elements to mark content. Note that /H1 has been role-mapped to /Head1 in this example. This is typically accomplished
by an authoring tool.
0 obj% Document catalog
<< /Type /Catalog
/Pages 100 0 R % Page tree
/StructTreeRoot 300 0 R % Structure tree root
>>
endobj
...
300 0 obj% Structure tree root
<< /Type /StructTreeRoot
/K [ 301 0 R % Two children: a chapter
304 0 R % and a paragraph
/RoleMap << /Chap /Sect % Mapping to standard structure types
/Head1 /H
/Para /P
>>
/ClassMap << /Normal 305 0 R >> % Class map containing one attribute class
/ParentTree 400 0 R % Number tree for parent elements
/ParentTreeNextKey 2 % Next key to use in parent tree
/IDTree 403 0 R % Name tree for element identifiers
>>
endobj
301 0 obj % Structure element for a chapter
<< /Type /StructElem
/S /Chap
/ID (Chap1) % Element identifier
/T (Chapter 1) % Human-readable title
/P 300 0 R % Parent is the structure tree root
/K [ 302 0 R % Two children: a section head
303 0 R % and a paragraph
>>
endobj
302 0 obj % Structure element for a section head
<< /Type /StructElem
/S /Head1
/ID (Sec1.1) % Element identifier
/T (Section 1.1) % Human-readable title
/P 301 0 R % Parent is the chapter
/Pg 101 1 R % Page containing content items
/A << /O /Layout % Attribute owned by Layout
/SpaceAfter 25
/SpaceBefore 0
/TextIndent 12.5
>>
/K 0 % Marked-content sequence 0
>>
endobj
...
Within marked content containers, headings can be marked up using
/Head
elements as follows for a first-level heading in
a PDF document:
BT % Start of text object
/Head1 <> % Start of marked-content sequence
BDC
...
(This is a first level heading. Hello world: ) Tj
...
EMC % End of marked-content sequence
...
ET % End of text object
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.4.3.2 (Paragraphlike Elements) in
PDF
1.7 (ISO 32000-1)
PDF
Accessibility Documentation:headings
PDF and Accessibility
Related Techniques
G141: Organizing a page using headings
Tests
Procedure
For all PDF content that is divided into separate sections, use
one of the following to verify that headings are tagged correctly:
Read the PDF document with a screen reader, listening to hear
that the list of headings is announced correctly.
Using a PDF editor,
make sure the headings are tagged correctly.
Use a tool that is capable of showing the /Head
entries
to open the PDF document and verify that headings are tagged
correctly.
Use a tool that exposes the document through the accessibility
API and verify that the headings are tagged correctly.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF10: Providing labels for interactive form controls in PDF documents
Applicability
Tagged PDF documents with forms.
PDF forms created using Adobe LiveCycle Designer.
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
Success Criterion 3.3.2 (Labels or Instructions)
How to Meet 3.3.2 (Labels or Instructions)
Understanding Success Criterion 3.3.2 (Labels or Instructions)
Success Criterion 4.1.2 (Name, Role, Value)
How to Meet 4.1.2 (Name, Role, Value)
Understanding Success Criterion 4.1.2 (Name, Role, Value)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF10
. Also see
PDF Technology Notes
Description
The objective of this technique is to ensure that users of assistive
technology are able to perceive form control labels and understand
how form controls are used.
Form controls allow users to interact with a PDF document by filling
in information or indicating choices which can then be submitted for
processing. Assistive technology users must be able to recognize and
understand the form fields, make selections, and provide input to complete
the forms, and submit the form, just as sighted users can. Understandable
labels that convey the purpose of each form control are essential to
form accessibility.
Form inputs generally have labels and instructions to help users understand
what information is required and how to fill in the form. Unless these
labels are programmatically associated with the relevant fields, assistive
technology might not be able to associate them correctly, and thus
users might not understand how to complete the form.
Using Adobe Acrobat Pro with documents with interactive forms, you
can make sure that the forms are accessible and usable by making sure
that programmatically associated labels that convey the purpose of
the fields are provided.
The heuristics used by assistive technology will sometimes use the
text label if a programmatically associated label cannot be found.
The TU entry (which is the tooltip) of the
field dictionary is the programmatically
associated label (see Example
3 below and Table 220 in
PDF
1.7 (ISO 32000-1)
). Therefore, add a tooltip to each field to provide
a label that assistive technology can interpret.
Placement rules
The table below lists the placement rules governing where Adobe LiveCycle
positions labels by default. Note that these rules assume left-to-right
text directionality. If your form requires different positioning (e.g.,
to accommodate PDF documents in languages that use right-to-left text
directionality), see
Repositioning form labels
in Example
2 below. In general, authors should review label positioning to make
sure it meets the requirements of their particular form.
Control Type
LiveCycle Placement Rules
Text input (including date/time and password fields)
Default placement for the label is to the left of the control.
If this is not possible, LiveCycle will attempt to place it
immediately above the control.
Checkbox
Default placement for the label is to the right of the check
box.
Radio button group
Default placement for the label for each individual radio
button is to the right of the button.
Create a visible caption for the radio button group by creating
static text and placing it to the left of or above the group.
(See
Labeling radio buttons
below.)
Combo box
Default placement for the label is to the left of the drop-down
list. If this is not possible, LiveCycle will attempt to place
it immediately above the control..
List box
Default placement for the label is above the list box.
Button
LiveCycle automatically places the label on the button;
it does not have to be positioned manually. Ensure that the
button's purpose is properly described in the label text.
Examples
Example 1: Providing labels using the Forms tool in Adobe Acrobat
9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
As noted in the Description, text labels added in an authoring tool
and then converted to PDF might be visually associated with the fields
but are not programmatically associated, and you should provide a tooltip.
In the Forms menu, select Add or Edit Fields...
For the field you want to edit, access the context menu and select
the Properties dialog.
In the General tab of the Properties dialog, type a description
for the form field in the Tooltip field.
Repeat for all form fields.
The following image shows the Properties dialog with a description
in the Tooltip field.
This example is shown in operation in the
working example of providing labels using the forms tool
Example 2: Providing labels to form controls in Adobe LiveCycle Designer
ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
LiveCycle Designer provides several options for associating descriptive
text and labels with form elements.
For sighted or low-vision users, it is important to properly position
the label adjacent to the control. For screen reader users, you should
also ensure that the label is programmatically associated with the
form control and that sufficient information is provided so that screen
reader users can readily complete and submit the form.
This example is shown in operation in the
working example of providing labels in LiveCycle Designer
Specifying accessible label text using the accessibility palette
In LiveCycle Designer, create or import a form. Then:
Enable the palette by selecting Window > Accessibility or by
pressing shift + F6.
The palette appears in LiveCycle Designer's right-hand panel.
Select an object in your form. The palette shows the object's
accessibility properties.
The label that a screen reader uses does not necessarily have to be
the same as the visual caption. In some cases, you may want to provide
more information about a form element's purpose.
To specify what text should be announced by the screen reader for
a particular object, you can use the Accessibility Palette's Screen
Reader Precedence drop down list. Text is announced in the order shown
in the list: custom text, tool tip, caption, and name.
Depending on the complexity and difficulty of your form, you must
decide which option best suits the requirements for your form.
By default, a screen reader searches for an object's text in order
shown in the image. Once descriptive text has been found for a control,
the search stops.
The image below shows an example of a text field with a visual caption
that might be unclear for screen reader users. One of the fields has
a caption of "Date" but screen reader users may want to know
the preferred date format (shown as screen text). So this text is provided
in the tooltip. Because a tooltip has a higher precedence than the
visual caption, the screen reader uses the tooltip.
Labeling radio buttons
When a screen reader user tabs into a radio button, the screen reader
needs to announce two items:
A general description of the purpose of the
group
of
buttons
A meaningful description for the purpose of
each
radio
button
To make radio buttons accessible:
In the Hierarchy palette, select the radio button group.
Select the Accessibility palette and in the Custom Screen Reader
Text box, type the speak text for the group. For example, type "Select
a method of payment."
In the Hierarchy palette, select the first radio button in the
group.
In the Object palette, select the Field tab. In the Item area,
select the item and type a meaningful value for the selected radio
button. For example, type "Cash."
Repeat steps 3 and 4 for each radio button in the group.
Repositioning form labels
The placement of a caption, or label, is important because users expect
them to be found at a particular location adjacent to the control.
For screen magnification users this is even more important, as they
might not be able to view both the control and the label at the same
time.
When you create an object, Adobe LiveCycle Designer automatically
positions the label as specified by the control type (see the table
in the Description above). For example, for a text field, the label
is positioned to the left of the control.
If you need to change the position of the label text (for example,
to accommodate right-to-left text directionality):
Select the object by moving the focus to it.
In the Layout palette, under Caption at the bottom of the palette,
select the position of your object from the Position drop-down list.
The resulting repositioned label is shown below. The label for the
Date text field has been moved from the left of the field to the line
above the field.
Example 3: Adding a tooltip to interactive form controls
The following code fragment illustrates the use of the TU entry to
provide a tooltip (or programmatically associated text label) for a
form field. This is typically accomplished by an authoring tool.
<< /AP -dict-
/DA /Helv 0 Tf 0 g
/DR -dict-
/F 0x4
/FT Tx % FT key set to Tx for Text Field
/P -dict-
/Rect -array-
/StructParent 0x1
/Subtype Widget
/T Date you are available % Partial field name Date
/TU Date you are available: use MM/DD/YYYY format % TU tool tip value serves as short description
/Type Annot
/V Pat Jones
>>
...

BT
/P <>BDC
/CS0 cs 0 scn
/TT0 1 Tf
-0.001 Tc 0.003 Tw 11.04 0 0 11.04 72 709.56 Tm
[(P)-6(le)-3(as)10(e)-3( )11(P)-6(rin)2(t)-3( Y)8(o)-7(u)2(r N)4(a)11(m)-6(e)]TJ
0 Tc 0 Tw 9.533 0 Td
( )Tj
-0.004 Tc 0.004 Tw 0.217 0 Td
[(\()-5(R)-4(e)5(q)-1(u)-1(i)-3(r)-3(e)-6(d)-1(\))]TJ
EMC
/P <>BDC
0 Tc 0 Tw 4.283 0 Td
[( )-2( )]TJ
EMC
/ArtifactSpan <>BDC
0.002 Tc -0.002 Tw 0.456 0 Td
[(__)11(___)11(___)11(___)11(___)11(_)11(____)11(___)11(___)11(__)]TJ
0 Tc 0 Tw 13.391 0 Td
( )Tj
EMC
ET

Resources
Resources are for information purposes only, no endorsement implied.
PDF
1.7 (ISO 32000-1)
Adobe
XML Forms Architecture (XFA)
PDF and Accessibility
Related Techniques
G131: Providing descriptive labels
G162: Positioning labels to maximize predictability of relationships
PDF23: Providing interactive form controls in PDF documents
PDF5: Indicating required form controls in PDF forms
PDF22: Indicating when user input falls outside the required format or
values in PDF forms
Tests
Procedure
For each form control, verify visually that the label is positioned
correctly in relation to the control.
For each form control, verify that the name is programmatically
associated with the control by one of the following:
Open the PDF document with a tool that is capable of showing
the name associated with the control and verify that the name
is associated correctly with the control.
Use a tool that exposes the document through the accessibility
API, and verify that the name is associated correctly with the
control.
Expected Results
#1 and #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF11: Providing links and link text using the Link annotation and the /Link structure element in PDF documents
Applicability
PDF documents that contain links
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
Success Criterion 2.1.1 (Keyboard)
How to Meet 2.1.1 (Keyboard)
Understanding Success Criterion 2.1.1 (Keyboard)
Success Criterion 2.1.3 (Keyboard (No Exception))
How to Meet 2.1.3 (Keyboard (No Exception))
Understanding Success Criterion 2.1.3 (Keyboard (No Exception))
Success Criterion 2.4.4 (Link Purpose (In Context))
How to Meet 2.4.4 (Link Purpose (In Context))
Understanding Success Criterion 2.4.4 (Link Purpose (In Context))
Note:
This technique must be combined with other techniques to meet
SC 2.4.4
. See
Understanding SC 2.4.4
for details.
Success Criterion 2.4.9 (Link Purpose (Link Only))
How to Meet 2.4.9 (Link Purpose (Link Only))
Understanding Success Criterion 2.4.9 (Link Purpose (Link Only))
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF11
. Also see
PDF Technology Notes
Description
The purpose of this technique is to show how link text in PDF documents
can be marked up to be recognizable by keyboard and assistive technology
users. That is, the link information is programmatically available
to user agents so that links are recognizable when presented in a different
format. This is typically accomplished by using a tool for authoring
PDF.
Links in PDF documents are represented by a Link tag and objects in
its sub-tree, consisting of a link object reference (or Link annotation)
and one or more text objects. The text object or objects inside the
Link tag are used by assistive technologies to provide a name for the
link.
The simplest way to provide links that comply with the WCAG success
criteria is to create them when authoring the document, before conversion
to PDF.
However, in some cases, it may not be possible to create the links
using the original authoring tool. In these cases, Adobe Acrobat Pro
can be used to create the link. But, because the tooltip created using
the Link dialog in Adobe Acrobat Pro is not accessible to screen readers,
be sure that the link text or the link context makes the purpose clear.
In all cases, link purpose should be made clear as described in the
general techniques:
G53:
Identifying the purpose of a link using link text combined with
the text of the enclosing sentence
G91:
Providing link text that describes the purpose of a link
Examples
Example 1: Creating a hyperlink in Microsoft Word 2007 before conversion
to PDF
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
To create a hyperlink in Microsoft Word, first locate the item (e.g.,
web page) to link to. Then:
Either
Select Insert on the ribbon and select Hyperlink in the Links
tools
Or, use the CTRL+K keyboard shortcut
On the Insert Hyperlink dialog, add the link destination and link
text.
Save the file as tagged PDF. (See the
PDF Technology Notes
.)
Example 2: Creating a hyperlink in OpenOffice.org Writer 2.2 before
conversion to PDF
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
On the Insert menu, select Hyperlink.
In the Hyperlink dialog, insert the target URI in the Target field
under Hyperlink Type.
Insert the link text in the Text field under Further Settings.
(You can also select the link text from the document text before
bringing up the dialog. The Text field will be filled in with the
selected text.)
Save the file as tagged PDF. (See the
PDF Technology Notes
.)
Example 3: Creating a hyperlink using the Create Link dialog in Adobe
Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Select the text that will become the link text.
Access the context menu and select Create Link.
3. Follow the instructions in the Create Link dialog to specify the
link appearance, as shown below.
Then select Next and specify the URI. The image below shows the resulting
hyperlink and tooltip.
This example is shown in operation in the
working example of creating a hyperlink in PDF
Example 4: Marking up link text using a /Link structure element
Link annotations in PDF documents are associated with a geometric
region of a page rather than a particular object in a content stream.
For this reason, link annotations alone are not useful for users with
visual impairments, or to applications that must determine which content
can be activated to invoke a hypertext link.
Tagged PDF /Link elements use PDF's logical structure to establish
the association between content items and link annotations, providing
functionality comparable to HTML hypertext links.
In HTML, the following example produces text containing a hypertext
link:
Here is some text with a link inside.
In PDF the page must be painted first and then a link annotation
placed over the area where the object action will occur.
The following code fragment shows PDF equivalent to the HTML above;
it uses link text displayed in blue and underlined. A second code fragment
follows, indicating the associated logical structure hierarchy. This
is typically accomplished by an authoring tool.
/P <> %Marked Content Sequence 0 (paragraph)
BDC %Begin marked content sequence
BT %Begin text object
/F1 11.04 Tf %set text font and size
1 0 0 1 72.024 709.54 Tm %set text matrix
0 g %set non stroking color to black
0 G %set stroke color to black
[(H)3(ere )-4(is s)10(o)5(m)-4(e)9( t)-3(e)9(xt)-3( )] TJ %Show text preceding the link" Here is some text"
ET %end text object
EMC %end marked content sequence

/Span <> %Marked Content Sequence 1 (underlined link text)
BDC %Begin marked content sequence
BT %Begin text object
1 0 0 1 152.42 709.54 Tm %set text matrix
0 0 1 rg %set non-stroking color to blue
0 0 1 RG %set stroke color to blue
[(with a )-2(li)3(n)14(k)] TJ %Show link text " with a link"
ET %end text object
0 0 1 rg %set stroke color to blue
152.42 707.62 45.984 0.72 re %rectangle operator - target area for the link
f* %fill the path using the even-odd rule
EMC %end marked content sequence

/P <> %Marked Content Sequence 2 (paragraph)
BDC %Begin marked content sequence
BT %begin text object
1 0 0 1 198.41 709.54 Tm %set text matrix
0 g %set non stroking color to black
0 G %set stroke color to black
[( )] TJ %empty text string showing white space
ET %end text object
BT %begin text object
1 0 0 1 200.93 709.54 Tm %set text matrix
[(in)5(sid)5(e.)] TJ %show text following the link "inside."
ET %end text
BT %begin text object
1 0 0 1 229.97 709.54 Tm %set text matrix
[( )] TJ %empty text string showing white space
ET %end text object
EMC %end marked content sequence
The following code fragment is an excerpt from the logical structure
that establishes the association between the content items and the
link annotation:
11 0 obj %Object ID 11, generation 0, obj keyword
<<<
/Obj 26 0 R %reference to Object 26
/Type/OBJR %this object describes an indirect object reference
>>]
/P 12 0 R
/Pg 17 0 R
/S/Link
>>
endobj

26 0 obj %object ID 26 which is referenced by the OBJR in Object 11
</BS
</Type/Border
/W 0
>>
/Border[0 0 0] %a colorless border
/H/I
/Rect[150.128 694.558 200.551 720.0] %the boundaries defining target area where link annotation is active
/StructParent 1
/Type/Annot %Structure element is an annotation
/Subtype/Link
>> %It is a link annotation
endobj
31 0 obj %Object 31, gen 0, obj
</URI(http://www.w3.org/WAI) %The Uniform resource identifier to resolve
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.4.4.2 (Link Elements) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
G53: Identifying the purpose of a link using link text combined with the text of the enclosing sentence
G91: Providing link text that describes the purpose of a link
PDF13: Providing replacement text using the /Alt entry for links in PDF
documents
Tests
Procedure
For each hyperlink, verify that the link is correctly tagged and the
link text is properly exposed:
Read the PDF document with a screen reader, listening to hear
that the link is read correctly and that it describes the purpose
of the link (i.e., its destination).
Visually scan the tag tree to verify that the link is tagged correctly
and the link text is exposed (for screen magnifier users and sighted
users with cognitive disabilities).
Use a tool that is capable of showing the /Link entry value to
open the PDF document and view the hyperlink and link text.
Use a tool that exposes the document through the accessibility
API and verify that the link has the correct link text.
Tab to each link and check that it can be followed to its target
by pressing Enter.
Expected Results
#1 or #2 or #3 or #4 is true.
#5 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF12: Providing name, role, value information for form fields in PDF documents
Applicability
Tagged PDF documents with interactive form fields.
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
Success Criterion 4.1.2 (Name, Role, Value)
How to Meet 4.1.2 (Name, Role, Value)
Understanding Success Criterion 4.1.2 (Name, Role, Value)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF12
. Also see
PDF Technology Notes
Description
The objective of this technique is to ensure that assistive technologies
can gather information about and interact with form controls in PDF
content.
The types of PDF form controls are: text input field, check box, radio
button, combo box, list box, and button.
Providing name, role, state, and value information for all form components
enables compatibility with assistive technology, such as screen readers,
screen magnifiers, and speech recognition software used by people with
disabilities.
The PDF specification defines how name, role, and value are set for
form controls in Section 12.7.4 (Field Types) of
PDF
1.7 (ISO 32000-1)
, as shown in the following table. The Comments column explains how Adobe Acrobat Pro displays the corresponding information.
Interactive Form Dictionary Entries
Used to Define
Comments
FT
Role
Controls that share field type also use field flags to set
the appropriate role. In Adobe Acrobat the role for form controls
is set automatically.
TU
Name
In Adobe Acrobat the TU entry value is provided via the Tooltip
field in the form control's Properties dialog. This should
not be confused with the T entry which is defined as the Name
in Acrobat's form control properties dialog - the name field
in the Properties dialog is not used to provide the name for
a control when read by assistive technologies.
CA
Name (Pushbuttons only)
In Adobe Acrobat the CA entry value is provided via the label
field in the form control's Properties dialog.
Value
The Value entry is set by the user interacting with the control,
where a value is needed.
DV
Default Value
In Adobe Acrobat the DV entry value can be set in the form
control's Properties dialog.
The following table describes how the role, name, value, and state
are defined for PDF form controls created using Adobe Acrobat Pro.
Adobe LiveCycle Designer provides the same controls as well as several
additional ones: see Example 2 below.
PDF form element
Role (FT entry)
Name (TU entry)
Value (V entry)
Configurable States
Text field
Text
/Tx
Tooltip
Default value (DV entry in field dictionary) can be set in
the Properties dialog. Value is entered by user.
Read Only, Required, Multiline, Password
Check box
Check box
/Btn
Tooltip
V entry is set to 'Yes' or 'No' depending on Checked state.
Read Only, Required, Checked
Radio button
Radio button
/Btn
(Field Flag set to 'Radio')
Tooltip
V entry is set to 'Yes' or 'No' depending on Checked state.
Read Only, Required, Checked
Combo box
Combo box
/Ch
(Field Flag set to 'Combo')
Tooltip
Default value (/DV) can be set in the Properties dialog.
Value is determined by user selection.
Read Only, Required
List box
Drop-down list
/Ch
Tooltip
Default value (/DV) can be set in the Properties dialog.
Value is determined by user selection.
Read Only, Required
Button
Push button
/Btn
(Field Flag set to 'Pushbutton')
Label (CA entry instead of TU entry)
Push buttons do not have or require a value.
Read Only, Required
Signature field
Text
/Sig
Tooltip
Default value (DV entry in field dictionary) can be set in
the Properties dialog. Value is entered by user.
Read Only, Required
Examples
Example 1: Specifying name, role, value and/or state for a form field
using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
This example uses a check box for illustration; the procedure is the
same for other form controls. In Form Editing mode:
Access the context menu for the form field you are creating or
modifying.
Select the Properties... dialog for the form field.
Specify the name by adding a value to the tool tip field. This
will used by the accessibility API as the Name for the control and
should usually be set to match the text used as a visual label for
the control.
Select the Options tab.
Specify the default value and the default state, if appropriate.
The image below shows the Check Box Properties dialog, open in the
General tab. (The Name field in the dialog is not needed for accessibility.)
The image below shows the Check Box Properties dialog, open in the
Options tab.
This example is shown in operation in the
working example of specifying name, role, value using Acrobat Pro
Example 2: Specifying name, value, and state for a form field using
Adobe LiveCycle Designer ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In Adobe LiveCycle Designer, you use the Object Library to create
form objects and the Object Palette to specify name, role, state or
value for the object.
The following image shows the Object Palette.
The following three images show the tabs in the Object palette. In
the first the Field tab is open for specifying the type (or role) of
the field.
The next image shows the Value tab, with options that can be applied
to the field.
The third images shows the Binding tab, specifying the name of the
field.
This example is shown in operation in the
working example of specifying name, role, value using LiveCycle Designer
Example 3: Adding a checkbox in a PDF document using the /Btn field
type
The following code fragment illustrates code that is typical for a
simple check box field such as shown in Examples 1 and 2. This is typically
accomplished by an authoring tool.
1 0 obj
<< /FT /Btn % Role
/TU Retiree % Name
/V /Yes % Value
/AS /Yes
/AP << /N << /Yes 2 0 R /Off 3 0 R>>
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 12.7.4 (Field Types) of
PDF
1.7 (ISO 32000-1)
Adobe
XML Forms Architecture (XFA)
PDF and Accessibility
Related Techniques
PDF23: Providing interactive form controls in PDF documents
PDF5: Indicating required form controls in PDF forms
PDF22: Indicating when user input falls outside the required format or
values in PDF forms
Tests
Procedure
For the form control, verify that name, role, and value/state
are specified by one of the following:
Use a screen reader to navigate to the form control and check
that it can be activated or that its value can be changed. Verify
that the name (tooltip) and role are announced.
Use a tool capable of showing the form field information to open the PDF document and verify that the form control has the correct name, role, value, and state (if appropriate) information.
Use a tool that exposes the document through the accessibility
API, and verify that the form control has the correct name, role,
value, and state (if appropriate) information.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF13: Providing replacement text using the /Alt entry for links in PDF
documents
Applicability
Tagged PDF documents that contain links.
This technique relates to:
Success Criterion 2.4.4 (Link Purpose (In Context))
How to Meet 2.4.4 (Link Purpose (In Context))
Understanding Success Criterion 2.4.4 (Link Purpose (In Context))
Note:
This technique must be combined with other techniques to meet
SC 2.4.4
. See
Understanding SC 2.4.4
for details.
Success Criterion 2.4.9 (Link Purpose (Link Only))
How to Meet 2.4.9 (Link Purpose (Link Only))
Understanding Success Criterion 2.4.9 (Link Purpose (Link Only))
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF13
. Also see
PDF Technology Notes
Description
The objective of this technique is to provide replacement link text
via the /Alt entry in the property list for a tag. This is usually
not necessary, but in some situations, additional information beyond
the visible link text is needed, particularly for screen reader users.
Screen readers can read visible link text, but replacing the screen
text with meaningful alternate text for links in a PDF document can
make links more accessible.
Links in PDF documents are represented by a Link tag and objects in
its sub-tree, consisting of a link object reference (or Link annotation)
and one or more text objects. The text object or objects inside the
Link tag are used by assistive technologies to provide a name for the
link.
Authors can replace the default link text by providing an /Alt entry
for the Link tag. When the Link tag has an /Alt entry, screen readers
ignore the value of any visible text objects in the Link tag and use
the /Alt entry value for the link text.
The simplest way to provide context-independent link text that complies
with the WCAG 2.0 success criteria is to create them when authoring
the document, before conversion to PDF. In some cases, it may not be
possible to create the links using the original authoring tool. When editing PDF documents with Adobe Acrobat Pro, the best way to create accessible links is to use the Create Link command.
Authors should make sure that the alternate text makes sense in context
of the screen text before and after the link.
Examples
Example 1: Adding alternate link text using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
The image below shows a document converted to PDF from Oracle Open
Office. Note that the visible link text is the URL for the link target.
A screen reader will read the entire URI as the link text.
To create more accessible link text for assistive technology:
In the View menu, open the Tag panel by selecting Navigation Panels > Tags.
Locate the Link tag in the tag tree, access the context menu for
the link, and select Properties.
In the TouchUp Properties dialog, in the Tags tab, enter replacement
text in the Alternate Text field. Screen readers will read this text
instead of the entire URI.
The next image shows the Link tag structure in the Tag panel.
The last image shows the Alternate Text specified in the Link tag's
TouchUp Properties dialog. A screen reader will read the Alternate
Text as the link text.
This example is shown in operation in the
working example of adding alternate link text (OpenOffice file)
and
working example of adding alternate link text (PDF file)
Example 2: Adding alternate link text in a PDF document using the
/Alt entry
The following code fragment illustrates code that is typical for alternative
text for a link. This is typically accomplished by an authoring tool.
32 0 obj
<<
/S/URI %Action type (required), must be URI for a URI action
/URI(http://www.boston.com/business/technology/) %Uniform resource identifier(required), the URI to be resolved
>>
endobj
The following illustrates how to specify alternate text for the
URL in the above link:
11 0 obj
<<
/Alt(Boston Globe technology page) %Alternate text entry
/K [ 1
<<
/Obj 27 0 R
/Type /OBJR %Object reference to the link
>>
/P 12 0 R
/Pg 18 0 R
/S
/Link
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.9.4 (Replacement Text) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
G53: Identifying the purpose of a link using link text combined with the text of the enclosing sentence
G91: Providing link text that describes the purpose of a link
G149: Using user interface components that are highlighted by the user agent when they receive focus
PDF11: Providing links and link text using the Link annotation and the /Link structure element in PDF documents
Tests
Procedure
For the hyperlink, verify that the alternate link text is properly
coded by one of the following:
Read the PDF document with a screen reader, listening to hear
that the alternate link text is read correctly.
Use a tool that is capable of showing the /Alt entry to open
the PDF document and view the hyperlink and alternate link text.
Use a tool that exposes the document through the accessibility
API and verify that the alternate link text is the text for the
link.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF14: Providing running headers and footers in PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 2.4.8 (Location)
How to Meet 2.4.8 (Location)
Understanding Success Criterion 2.4.8 (Location)
Success Criterion 3.2.3 (Consistent Navigation)
How to Meet 3.2.3 (Consistent Navigation)
Understanding Success Criterion 3.2.3 (Consistent Navigation)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF14
. Also see
PDF Technology Notes
Description
The objective of this technique is to help users locate themselves
in a document by providing running headers and footers via pagination
artifacts. This is normally accomplished using a tool for authoring
PDF.
Running headers and footers help make content easier to use and understandable
by providing repeated information in a consistent and predictable way.
The content of headers and footers will vary widely depending on the
document scope and content, the audience, and design decisions. Some
examples of location information that may be used in headers and footers
are listed below. Whether the information appears in a header or a
footer is often a design decision; page numbers often appear in footers
but they may alternatively appear in headers.
Document title
Current chapter and/or section in the document
Page numbers with location information such as, "Page 3-4" or "Page
9 of 15."
Author and/or date information.
Consistency helps users with cognitive limitations, screen-reader
users and low-vision magnifier users, and users with intellectual disabilities
understand content more readily.
The easiest way to provide page headers and footers is in the authoring
tool for the document. Authoring tools typically provide features for
creating header and footer text and information (such as page numbers).
However, if after converting your document to PDF, you need to add
or modify page headers and footers, authoring or repair tools like Adobe Acrobat Pro's Header & Footer
tools can be used. In all cases, the tools generate page headers and
footers in consistent and predictable layout, format, and text.
Examples
Example 1: Adding running headers and footers using Microsoft Word
2007
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In Microsoft Word, use the Insert ribbon, which allows you to specify
header, footer, and page number information and layout, as shown in
the following images.
You can use these tools to specify headers and footers as shown in
the following images:
When converted to PDF, the page headers and footers appear in the
document.
This example is shown in operation in the
working example of adding running headers using Word (Word file)
and
working example of adding running headers using Word (PDF file)
Example 2: Adding running headers and footers using OpenOffice.org
Writer 2.2
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In OpenOffice.org Writer, use the Insert > Header and Insert > Footer
tools, which allow you to specify header and footer information and
layout, as shown in the following images.
When converted to PDF, the page headers and footers appear in the
document as they do in the converted Word document in Example 1.
This example is shown in operation in the
working example of adding running headers using OpenOffice Writer (OpenOffice file)
and
working example of adding running headers using OpenOffice Writer (PDF file)
Example 3: Adding running headers and footers to PDF documents using
Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In Adobe Acrobat Pro, you can add or modify headers and footers:
Select Document > Header & Footer > Add...
In the Add Header and Footer tool, specify text and formats for
headers and footers in your document.
Use the Previews to make sure the text, fonts, and layout are
as you want them for your document.
The image below shows Acrobat Pro's Add Header and Footer tool.
Example 4: Marking a running header or footer as a pagination artifact
in a PDF document using an /Artifact tag or property list
The PDF specification allows running headers and footers to be marked
as "pagination artifacts" as defined in section 14.8.2.2 "Real
Content and Artifacts," of
PDF
1.7 (ISO 32000-1)
An artifact is explicitly distinguished from real content by enclosing
it in a marked-content sequence with the /Artifact tag.
/Artifact
BMC
...
EMC
or
/Artifact propertyList
BDC
...
EMC
The first is used to identify a generic artifact; the second is
used for artifacts that have an associated property list. Note: to
aid in text reflow, artifacts should be defined with property lists
whenever possible. Artifacts lacking a specified bounding box are
likely to be discarded during reflow.
Property list entries for artifacts include Type, BBox, Attached,
and Subtype.
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.2.2 (Real Content and Artifacts) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
G61: Presenting repeated components in the same relative order each time they
appear
PDF9: Providing headings by marking content with heading tags in PDF documents
PDF2: Creating bookmarks in PDF documents
Tests
Procedure
Check that running headers and/or footers are provided and contain
information to help users locate themselves within the document (such
as page numbers or chapter numbers).
If section headers are used in the running header or footer, check
that the section header and the running header or footer are consistent.
Expected Results
#1 and #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF15: Providing submit buttons with the submit-form action in PDF forms
Applicability
Tagged PDF documents with forms.
This technique relates to:
Success Criterion 3.2.2 (On Input)
How to Meet 3.2.2 (On Input)
Understanding Success Criterion 3.2.2 (On Input)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF15
. Also see
PDF Technology Notes
Description
The objective of this technique is to provide a mechanism that allows
users to explicitly request a change of context using the submit-form
action in a PDF form. The intended use of a submit button is to generate
an HTTP request that submits data entered in a form, so it is an appropriate
control to use for causing a change of context. In PDF documents, submit buttons are normally implemented using a tool for authoring PDF.
Examples 1 and 2 demonstrate how to add a submit button using specific
authoring tools. There are other PDF tools that perform similar
functions. Check the functionality provided by
PDF Authoring Tools that Provide Accessibility Support
Examples
Example 1: Adding a submit button using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
From the toolbar, select Forms > Form Tools > Button and
create a button on the form.
Access the context menu for the button and select Properties...
to open the Button Properties dialog.
In the General tab, provide a tooltip for the button.
In the Options tab, choose an option in the Layout menu for the
button label, icon image, or both. Then, type text in the Label box
to identify the button as a submit button and/or click Choose Icon
and locate the image file you want to use.
In the Actions tab:
For Select Trigger, choose Mouse Up. (The Mouse Up event is
keyboard accessible and, in addition, ensures that the button
will not change context unexpectedly, as it might with, e.g.,
a Mouse Enter event.)
For Select Action, choose Submit A Form.
Click Add.
In the Add dialog, enter a URL to collect data on a server or
collect form data as e-mail attachments.
The following image shows the Options tab on the Button Properties
dialog.
The following image shows the Actions tab on the Button Properties
dialog.
Example 2: Adding a submit button using Adobe LiveCycle Designer
ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
On the Insert > Standard menu, select the HTTP Submit Button
item.
On the Object panel for the HTTP Submit Button, insert the URL
for form-submission processing.
The following image shows the Standard menu with the list of form
controls.
The following image shows the Object panel with the URL and other
fields for button appearance.
Example 3: Adding a script action to a submit button in a PDF document
using JavaScript
The following JavaScript code illustrates the use of a script to specify
the submit-form action. To add this script to the form field:
Open the Button Properties dialog, as shown in Example 1, and
select the Actions tab
Select Run a JavaScript from the drop-down list, and select the
Add button
Enter JavaScript code in the JavaScript Editor dialog, for example:
var aSubmitFields = new Array( "name", "id", "juser" );
this.submitForm({
cURL: "http://www.example.com/cgi-bin/myscript.cgi#FDF",
aFields: aSubmitFields,
cSubmitAs: "FDF" // the default, not needed here
});
The following images illustrate this process:
This example is shown in operation in the
working example of adding a script action to a submit button
Resources
Resources are for information purposes only, no endorsement implied.
Section 12.7.5.2 (Submit-Form Action) in
PDF
1.7 (ISO 32000-1)
Create
submission forms in LiveCycle Designer
XML
Forms Architecture (XFA) Specification Version 2.5
PDF and Accessibility
Related Techniques
G80: Providing a submit button to initiate a change of context
PDF23: Providing interactive form controls in PDF documents
PDF12: Providing name, role, value information for form fields in PDF documents
Tests
Procedure
For each page that submits a form, visually verify that the form
contains a submit button and check one of the following:
Tab to the button and check that it submits the form in response
to user action to select the button.
Open the PDF document with a tool that is capable of showing
the submit-form action and check that the button action is to
submit the form.
Expected Results
#1 is true for each page that contains a form.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF16: Setting the default language using the /Lang entry in the document
catalog of a PDF document
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 3.1.1 (Language of Page)
How to Meet 3.1.1 (Language of Page)
Understanding Success Criterion 3.1.1 (Language of Page)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF16
. Also see
PDF Technology Notes
Description
The objective of this technique is to specify a document's default
language by setting the /Lang entry in the document catalog. This is
normally accomplished using a tool for authoring PDF.
Both assistive technologies and conventional user agents can render
text more accurately when the language of the document is identified.
Screen readers can load the correct pronunciation rules. Visual browsers
can display characters and scripts correctly. Media players can show
captions correctly. As a result, users with disabilities are better
able to understand the content.
Examples
Example 1: Adding a /Lang entry to specify the default document language
using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Open the document in Adobe Acrobat Pro
From the File menu, select "Properties..."
In the "Properties" dialog, select the "Advanced" tab
In the "Reading Options" field, select the default language
from the "Language" combo box
Note:
Acrobat includes 16 preset language selections.
If you need to specify a language that is not on the list, such as
Russian, you must type the ISO 639 code for the language, not its name.
This example is shown in operation in the
working example of adding a /Lang entry using Acrobat Pro
Example 2: Specifying the default document language in a PDF document
using Microsoft Word 2007
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Documents authored in Microsoft Word: "In some instances, even
if the document language has been specified in the source file, the
information about document language is not conveyed to the PDFMaker.
Setting the language for an entire document in the Document Properties
dialog box [see Example 1] corrects all errors related to this option."(
Adobe®
Acrobat® 9 Pro Accessibility Guide: Creating Accessible PDF from Microsoft®
Word
Example 3: Specifying the default document language in a PDF document
using a /Lang entry
The natural language used for text in a document is determined in
a hierarchical fashion, based on whether an optional /Lang entry is
present in any of several possible locations. At the highest level,
the document's default language may be specified by a /Lang entry in
the document catalog.
The following code fragment illustrates code that is typical for using
the /Lang entry in the document catalog for a document's default language
(in this case, US English). (This is typically accomplished by an authoring
tool.)
1 0 obj
<< /Type /Catalog
...
/Lang (en-US)
...
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.9.2 (Natural Language Specification) in
PDF
1.7 (ISO 32000-1)
ISO
639-2 Codes
PDF
Reference 1.6, 10.8.1 Natural Language Specification (PDF 8.7 Mb)
PDF
Standards: Natural Language Specification
Adobe®
Acrobat® 9 Pro Accessibility Guide: Creating Accessible PDF from
Microsoft® Word
PDF and Accessibility
Related Techniques
PDF19: Specifying the language for a passage or phrase with the Lang entry
in PDF documents
Tests
Procedure
Verify that the default language for the document is correctly
specified by applying one of the following:
Read the PDF document with a screen reader, listening to hear
that the text is read in the correct natural language.
Using a PDF editor, check that the language is
set to the default document language.
Use a tool which is capable of showing the /Lang entry value
in the document catalog to open the PDF document and view the
language settings.
Use a tool that exposes the document through the accessibility
API and verify that the language is set to the default language.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF17: Specifying consistent page numbering for PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
Success Criterion 2.4.8 (Location)
How to Meet 2.4.8 (Location)
Understanding Success Criterion 2.4.8 (Location)
Success Criterion 3.2.3 (Consistent Navigation)
How to Meet 3.2.3 (Consistent Navigation)
Understanding Success Criterion 3.2.3 (Consistent Navigation)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF17
. Also see
PDF Technology Notes
Description
The objective of this technique is to help users locate themselves in a document by ensuring that the page numbering displayed in the PDF viewer page controls has the same page numbering as the document. For example, Adobe Acrobat Pro and Reader display page numbers in the Page Navigation toolbar. The page number format is specified by the /PageLabels entry in the Document Catalog.
Many documents use specific page number formats within a document. Commonly, front matter is numbered with lowercase Roman numerals. The main content, starting on the page numbered 1, may actually be the fifth or sixth page in the document. Similarly, appendices may begin with page number 1 plus a prefix of the appendix letter (e.g., "A-1").
Authors should make sure that the page numbering of their converted documents is reflected in any page number displays in their user agent. Consistency in presenting the document's page numbers will help make navigating the document more predictable and understandable.
As an example, if /PageLabels has not been provided to describe the page number formatting, the page numbering scheme will not be reflected in the Page Navigation toolbar in Adobe Acrobat Pro or Reader. This toolbar displays the page number in a text box, which users can change to move to another page. In addition, users can select the arrows to move one page up or down in the document. The toolbar also displays the relative page number location. In the image below, the default display indicates the user is on page 1 of 4 pages.
A more direct way of going to a page is to use the shortcut for the View > Page Navigation > Page menu item. On Windows, this shortcut is "Ctrl + Shift + N"; on Mac OS, it is "Cmd + Shift + N". This brings up a dialog box to go to a specific page number.
Examples
Example 1: Editing PDF page number formatting specifications using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
The example document converted from Microsoft Word 2007 has 4 pages, numbered
i, ii, iii, 1. The image below shows the Word document with lowercase
Roman numeral page numbering specified In Word using:
Insert ribbon > Page number > Page Number Format
In this document, a new section has been created with page numbering
beginning with Arabic numeral 1 on the fourth page of the document. The document
was then converted to PDF from Word.
In Adobe Acrobat Pro, Select View > Navigation Panels > Pages.
The following image shows the page thumbnails in the Pages panel
and the Page Navigation toolbar. Both the thumbnails and the toolbar
use Arabic page numbers.
To correct the page numbers:
Select the pages to be renumbered
Access the context menu for the selected pages and select Number
Pages
In the Page Numbering dialog, select the lowercase Roman numeral
style and the starting page (1 by default, which is correct in this
case)
Select OK
The following image shows the Page Numbering dialog and selections.
Follow the same process to change the fourth page number to Arabic
numeral 1.
The following image shows the correct page numbers for the 4 pages.
Note that page iii is selected in the Pages panel and the Page Navigation
toolbar shows iii in the text area. In addition, the relative location
in the document is shown at the right of the toolbar: "(3 of 4)."
This example is shown in operation in the
working example of specifying page numbers in a document converted from Word (Word file)
and
working example of specifying page numbers in a document converted from Word (PDF file)
Example 2: Specifying page numbers using the /PageLabels entry
The following code fragment illustrates code that is typical for specifying
multiple page numbering schemes in a document.
The example below is for a document with pages labeled:
Example:
i, ii, iii, iv, 1, 2, 3, A-8, A-9, …
This numbering scheme requires 3 page-label dictionaries (for lowercase
Roman, Arabic, and prefixed numbers)
1 0 obj
<< /Type /Catalog
/PageLabels << /Nums [ 0 << /S /r >> % lowercase Roman numerals
4 << /S /D >> % Arabic numerals
7 << /S /D % Arabic numerals with ...
/P (A-) % the prefix "A-"...
/St 8 % starting at page 8
>>
>>
>>
endobj
Page labels are specified as follows:
/S
specifies the numbering style for page numbers:
/D
- Arabic numerals (1,2,3...)
/r
- lowercase Roman numerals (i, ii, iii,...)
/R
- uppercase Roman numerals (I, II, III,...)
/A
- uppercase letters (A-Z)
/a
- lowercase letters (a-z)
/P
(optional) - page number prefix
/St
(optional) - the value of the first page number in the range
(default: 1)
Resources
Resources are for information purposes only, no endorsement implied.
Section 12.4.2 (Page Labels)
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
PDF14: Providing running headers and footers in PDF documents
Tests
Procedure
For every section in the document that uses a different pagination
format, check that the page navigation feature uses the same format
used on the document pages:
Select the pages that begin a new pagination
format and visually verify that the same format and page number
is shown in the page navigation feature.
Using a screen reader, check that the page number announced
in the page navigation feature is the same as the page number
announced on the document page.
Using a tool that is capable of showing the /PageLabels entries,
open the PDF document and view the entries.
Use a tool that exposes the document through the accessibility
API, and verify that the /PageLabels entries are specified correctly.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF18: Specifying the document title using the Title entry in the document
information dictionary of a PDF document
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 2.4.2 (Page Titled)
How to Meet 2.4.2 (Page Titled)
Understanding Success Criterion 2.4.2 (Page Titled)
Note:
This technique must be combined with other techniques to meet
SC 2.4.2
. See
Understanding SC 2.4.2
for details.
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF18
. Also see
PDF Technology Notes
Description
The intent of this technique is to show how a descriptive title for
a PDF document can be specified for assistive technology by using the
/Title entry in the document information dictionary and by setting
the DisplayDocTitle flag to True in a viewer preferences dictionary.
This is typically accomplished by using a tool for authoring PDF.
Document titles identify the current location without requiring users
to read or interpret page content. User agents make the title of the
page easily available to the user for identifying the page. For instance,
a user agent may display the page title in the window title bar or
as the name of the tab containing the page.
Examples
Example 1: Setting the document title in the metadata and specifying
that the title be displayed in the title bar using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Open the PDF document in Adobe Acrobat Pro:
Select File > Properties
Select the Description tab to view the metadata in the document,
including the document information dictionary
Modify the Title field to add or change the document's Title entry
Note that, with Adobe Acrobat installed, you can also enter and read
the data properties information from the desktop. Access the file's
context menu, choose Properties, and select the PDF tab. Any information
you type or edit in this dialog box also appears in the Document Properties
Description when you open the file.
To display the document title in the title bar of a user agent:
Select File > Properties
Select the Initial View tab
In the Window Options section, select Document Title in the Show
pull-down list.
The title is displayed in the title bar, as shown in the image below.
This example is shown in operation in the
working example of displaying document title in the title bar
Example 2: A /Title entry in the document information dictionary
of a PDF document
The following code fragment illustrates code that is typical for providing
a /Title entry in a document information dictionary that contains a
document title.
1 0 obj
<< /Title (Applying Guerrilla Tactics to Usability Testing by People with Disabilities)
/Author (Mary Smith)
/CreationDate (D:19970915110347-08'00')
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
PDF and Accessibility
Section 14.3.3 (Document Information Dictionary) in
PDF
1.7 (ISO 32000-1)
PDF
Reference 1.6, TITLE entry of the document information dictionary
Related Techniques
G88: Providing descriptive titles for Web pages
Tests
Procedure
Verify that the title for the document is correctly specified and
displayed in the user agent title bar by applying one of the following:
Open the PDF document with a screen reader, listening to hear
that the document title is read correctly.
Using a PDF editor, check that the document title is specified.
Select the Initial View tab to check that the title will be displayed.
Use a tool which is capable of showing the /Title entry value
in the document catalog to open the PDF document and view the
/Title entry and /DisplayDocTitle flag settings.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF19: Specifying the language for a passage or phrase with the Lang entry
in PDF documents
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 3.1.1 (Language of Page)
How to Meet 3.1.1 (Language of Page)
Understanding Success Criterion 3.1.1 (Language of Page)
Success Criterion 3.1.2 (Language of Parts)
How to Meet 3.1.2 (Language of Parts)
Understanding Success Criterion 3.1.2 (Language of Parts)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF19
. Also see
PDF Technology Notes
Description
The objective of this technique is to specify the language of a passage,
phrase, or word using the /Lang entry to provide information in the
PDF document that user agents need to present text and other linguistic
content correctly. This is normally accomplished using a tool for authoring
PDF.
Both assistive technologies and conventional user agents can render
text more accurately when the language is identified. Screen readers
can load the correct pronunciation rules. As a result, users with disabilities are better able to understand
the content.
Note:
This technique can be used to set the default
language for the entire document if the entire document is contained
in the container or tag. In this case, this technique would apply to
Success Criterion 3.1.1.
Examples
Example 1: Adding a /Lang entry to specify the language for a paragraph
using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
In the Tools menu, select Advanced Editing.
Select the TouchUp Reading Order Tool.
Click the Show Order Panel button in the TouchUp Reading Order
Tool
Select the Tags tab in the Show Order Panel and select the paragraph
that is in the different language. You can also use the Options menu
in the Tags tab: select Find Tag from Selection.
Right-click the selection and select Properties in the context
menu.
In the Tags tab in the Properties dialog, select the language
from the drop-down list.
Note:
Acrobat includes 16 preset language selections.
If you need to specify a language that is not on the list, such as
Russian, you must type the ISO 639 code for the language, not its name.
Example 2: Adding a /Lang entry to specify the language for a specific
word or phrase using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Select the word or phrase that is in a different language and
create a tag for it in the Reading Order Panel (e.g., Text).
Open the Tags tab in the Show Order Panel and select the tagged
word or phrase that is in the different language. You can also use
the Options menu in the Tags tab: select Create Tag from Selection.
Right-click the selection and select Properties in the context
menu.
In the Tags tab in the Properties dialog, select the language
from the drop-down list.
When you tag a word or phrase, Acrobat splits the original content
into three document content tags: one for the text that precedes your
selection, one for the selection, and one for the text that follows
the selection. As needed, drag the document content tag for the selected
text into position between the other two tags, so that the text reads
in the proper order. All three tags must also be at the same level
beneath their parent tag. Drag them into place if they are not.
This example is shown in operation in the
working example of marking a specific word or phrase in Acrobat Pro
Example 3: Specifying the language for a word or phrase in a PDF
document using a /Lang entry
Below the level of the default document language, the language for
a passage may be specified for the following items:
Marked-content sequences that are not in the structure hierarchy,
through a /Lang entry in a property list attached to the marked-content
sequence with a Span tag.
Structure elements of any type, through a /Lang entry in the structure
element dictionary.
The following code fragment illustrates code that is typical for using
the /Lang entry to override the default document language by specifying
a marked-content sequence within a page's content stream:
/P % Start of marked-content sequence
BDC
(See you later, or in Spanish you would say, ) Tj
/Span << /Lang (es-MX) >>% Start of nested marked-content sequence
BDC
(Hasta la vista.) Tj
EMC% End of nested marked-content sequence
EMC% End of marked-content sequence
The following code fragment illustrates code that is typical for
using the /Lang entry in the structure element dictionary. In this
case, the /Lang entry applies to the marked-content sequence having
an MCID (marked-content identifier) value of 0 within the indicated
page's content stream.
1 0 obj% Structure element
<< /Type /StructElem
/S /Span% Structure type
/P /P% Parent in structure hierarchy
/K<< /Type /MCR
/Pg 2 0 R% Page containing marked-content sequence
/MCID 0% Marked-content identifier
>>
/Lang (es-MX)% Language specification for this element
>>
endobj
2 0 obj% Page object
<< /Type /Page
/Contents 3 0 R% Content stream
>>
endobj
3 0 obj% Page's content stream
<< /Length … >>
stream
BT
/P % Start of marked-content sequence
BDC
(See you later, or in Spanish you would say, ) Tj
/Span << /MCID 0 >>% Start of nested marked-content sequence
BDC
(Hasta la vista.) Tj
EMC% End of nested marked-content sequence
EMC% End of marked-content sequence
ET
endstream
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.9.2 (Natural Language Specification) in
PDF
1.7 (ISO 32000-1)
ISO
639-2 Codes
PDF
Reference 1.6, 10.8.1 Natural Language Specification (PDF 8.7 Mb)
PDF
Standards: Natural Language Specification
Adobe®
Acrobat® 9 Pro Accessibility Guide: Creating Accessible PDF from
Microsoft® Word
PDF and Accessibility
Related Techniques
PDF16: Setting the default language using the /Lang entry in the document
catalog of a PDF document
Tests
Procedure
Verify that the language of a passage, phrase, or word that differs
from the language of the surrounding text is correctly specified
by a /Lang entry on an enclosing tag or container:
Read the PDF document with a screen reader that supports the language of the phrase and the language of the surrounding text, listening to hear
that the text is read in the correct natural language.
Using a PDF editor, select the word or phrase that is in the different language and check that the language is set correctly.
Use a tool which is capable of showing the /Lang entry value
to open the PDF document and view the language settings.
Use a tool that exposes the document through the accessibility
API and verify that the language for the passage or phrase is
set correctly.
Verify that if the container or tag contains the entire document,
the language setting is the language intended as the default for
the document.
Expected Results
#1 and #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF20: Using Adobe Acrobat Pro's Table Editor to repair mistagged tables
Applicability
Tagged PDF documents with tables.
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF20
. Also see
PDF Technology Notes
Description
The purpose of this technique is to show how table cells in PDF documents
can be marked up so that the logical relationships among rows and columns
are preserved and recognized by assistive technology. This is typically
accomplished by using a tool for authoring PDF.
However, tables converted to PDF may have incorrectly merged or split
table cells, even if they were marked up correctly in the authoring
tool. Authors can ensure that table cells are structured properly by
using the Table Editor in Adobe Acrobat Pro's TouchUp Reading Order
tool.
Examples
Example 1: Repairing table cells using the Table Editor in the TouchUp
Reading Order tool in Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
This example uses a table that was marked up correctly when it was
created in Microsoft Word. Some table headers span two rows in the
header row; one table header spans two columns.
To check the table in the PDF document:
Advanced > Accessibility > TouchUp Reading Order...
Select the table by clicking the number in the top left hand corner
of the table (3 in the reading order in the image below).
Select the Table Editor button on the TouchUp Reading Order panel.
The table cells will be outlined in red and labeled with their tags.
The red outlines may not exactly match up to the table cells but
you should be able to determine if the cells are tagged correctly.
The following image shows the example table in the TouchUp Reading
Order tool. Note that the Results header appears to span two sub-headers
and the other headers to the left span the two rows in the Results
header.
The following images shows the example table in the Table Editor.
The cells are outlined in red, and the tab for each cell is displayed.
Upon conversion, the Results header was incorrectly split and does
not span its two sub-headers. The headers to the right were incorrectly
split into 2 cells each and do not span the Results headers. In addition,
the incorrectly split cells were merged into one cell.
To repair the Results header:
Select the header in the table (it will be outlined in blue when
selected)
Access the context menu
Select Table Cell Properties...
In the Table Cell Properties dialog, change the Column Span from
1 to 2
Press OK. You'll get a warning that the change might result in
a malformed table structure. In this case, the change is correct.
The cell you changed should change color to show the new span, as
shown in the following image.
Similarly, to repair the incorrectly split header cells to the left
of Results header:
Select the top cell in the column (it will be outlined in blue
when selected)
Access the context menu
Select Table Cell Properties...
In the Table Cell Properties dialog, change the Row Span from
1 to 2
Press OK. The following image shows the correction being made
to the last header cell, with the corrected header cells to its left.
The following image shows the repaired example table.
This example is shown in operation in the
working example of repairing table structure (Word file)
and
working example of repairing table structure (PDF file)
Example 2: Marking up a table using table structure elements
The following code fragment illustrates code that is typical for a
simple table (header row and data row) such as shown in Examples 1-3:
95 0 obj %Structure element for a table
<<
/A 39 0 R
/K[96 0 R 101 0 R 106 0 R 111 0 R]
/P 93 0 R
/S/Table %standard structure type is table
>>
endobj
96 0 obj %Structure element for a table row
<<
/K[97 0 R 98 0 R 99 0 R 100 0 R]
/P 95 0 R
/S/TR %standard structure type is table row
>>
endobj
97 0 obj %Structure element for a table header
</K 1
/P 96 0 R
/S/TH %standard structure type is table head
/Pg 8 0 R
>>
endobj
104 0 obj %Structure element for table data (cell contents)
<<
/A 29 0 R
/K 7
/P 101 0 R
/S/TD %standard structure type is table data
/Pg 8 0 R
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
PDF and Accessibility
14.8.4.3.4 (Table Elements) in
PDF
1.7 (ISO 32000-1)
Related Techniques
H51: Using table markup to present tabular information
PDF6: Using table elements for table markup in PDF Documents
Tests
Procedure
For a table that has been repaired with the Table Editor, confirm
one of the following:
Read the PDF document with a screen reader, listening to hear
that the tabular information is presented in a way that preserves
logical relationships among the table header and data cells.
(Configure the screen reader to not use heuristics to read table
header cells.)
Using a PDF editor, verify that the appropriate
TR
TH
and
TD
tags are in the proper reading order and hierarchy
in the table tree.
Use a tool which is capable of showing the table elements
to open the PDF document, view the table structure, and verify
that it contains the appropriate TR, TH, and TD structures.
Use a tool that exposes the document through the accessibility
API, and verify that the table structure contains the appropriate
TR, TH, and TD structures, and that they are in the proper reading
order and hierarchy.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF21: Using List tags for lists in PDF documents
Applicability
Tagged PDF documents with lists.
This technique relates to:
Success Criterion 1.3.1 (Info and Relationships)
How to Meet 1.3.1 (Info and Relationships)
Understanding Success Criterion 1.3.1 (Info and Relationships)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF21
. Also see
PDF Technology Notes
Description
The intent of this technique is to create lists of related items using
list elements appropriate for their purposes. PDF files containing
lists are normally created or repaired using a tool for authoring PDF.
When markup is used that visually formats items as a list but does
not indicate the list relationship, users may have difficulty navigating
the information. An example of such visual formatting is simply using
line-breaks to separate list items.
Some assistive technologies allow users to navigate from list to list
or item to item. If the lists are not correctly formatted with list
tags, these users will have difficulty understanding the list content.
The easiest way to create lists in PDF content is to format them properly
using list markup in the authoring tool, for example, Microsoft Word
or OpenOffice.org Writer. However, if you do not have access to the
source file and authoring tool, you can use Acrobat Pro's TouchUp Reading
Order tool and the Tags panel.
The
PDF
specification
defines list structure in section 14.8.4.3.3 (List
Elements). The structure types for lists in PDF documents are:
L - the List tag, which contains one or more LI tags.
LI - the List Item tag. List item tags can contain Lbl and LBody
tags.
Lbl - the list item label. Contains distinguishing information
such as a item number or bullet character.
LBody - the list item body. Contains list item content, or in
the case of a nested list, it may contain additional List tag trees.
Examples
Example 1: Adding lists to Microsoft Word 2007 documents
This example is shown with Microsoft Word. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
On the Home ribbon, use the lists tools to create or repair lists
in Word documents. This is the easiest way to ensure that lists are
formatted correctly when they are converted to PDF.
In the image below, the numbered and bullet lists were created using
the list tools. The third list did not use the list tool (see the ribbon)
and the list will not be tagged as list elements when converted to
PDF.
Example 2: Adding lists to OpenOffice.org Writer 2.2 documents
This example is shown with OpenOffice.org Writer. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Use the Bullets and Numbering tool to create or repair lists in OpenOffice.org
Writer documents. This is the easiest way to ensure that lists are
formatted correctly when they are converted to PDF.
In the image below, the numbered and bullet lists were created using
the list tools. The third list did not use the list tool (see the toolbar)
and the list will not be tagged as list elements when converted to
PDF.
This example is shown in operation in the
working example of adding lists to OpenOffice Writer documents
Example 3: Ensuring that lists are correctly formatted using Adobe
Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software tools that perform similar functions. See the list of other software tools in
PDF Authoring Tools that Provide Accessibility Support
View > Navigation Panels... > Tags
Inspect the lists in the document to determine which, if any,
are not formatted properly.
In the following image, the third list is formatted as text. The list
items are separated only by line-breaks. Assistive technology may not
be able to render the list intelligibly for users.
To repair the list, use the Tags panel to create list tags in the
content.
The following image shows the resulting first list item correctly
formatted.
This example is shown in operation in the
working example of ensuring lists are properly formatted in Acrobat Pro
Example 4: Marking up lists using List structure elements
The following code fragment illustrates code that is typical marking
up a list hierarchy in PDF documents. It uses the simple numbered list
in the previous examples. This is typically accomplished by an authoring
tool.
4 0 obj
</Contents 5 0 R
>>

endobj
5 0 obj
<< /Length 3 0 R >>
stream
/P <> BDC
BT T* (The most popular sports are:) Tj ET EMC
/Lbl <> BDC
BT T* (1. ) Tj ET EMC
/LBody <> /BDC
BT (Snow-shoeing ) Tj ET EMC
/Lbl <> BDC
BT T* (2. ) Tj ET EMC
/LBody <> /BDC
BT (Ice-skating ) Tj ET EMC
/Lbl <> BDC
BT T* (3. ) Tj ET EMC
/LBody <> /BDC
BT (Skiing ) Tj ET EMC
endstream
endobj

101 0 obj % Structure element for intro paragraph to list ("The most popular sports are:")
<< /Type /StructElem
/S /P
/P 201 0 R
/Pg 4 0 R
/K 1
>>
endobj

111 0 obj % Structure element for first item, list label (Lbl): "1."
<< /Type /StructElem
/S /Lbl
/P 211 0 R
/Pg 4 0 R
/K 11
>>
endobj

112 0 obj
<< /Type /StructElem % Structure element for first item, list text (LBody): ("Snow-shoeing")
/S /LBody
/P 211 0 R
/Pg 4 0 R
/K 12
>>
endobj

... [ objects 121-122 and 131-132, referencing MCIDs 21-22 and 31-32 are omitted in the interest of space. ]

201 0 obj
<< /Type /StructElem
/S /Caption % Intro paragraph
/P 400 0 R
/K [101 0 R]
>>
endobj

211 0 obj
<< /Type /StructElem
/S /LI % List item for "1. Snow-shoeing"
/P 400 0 R
/K [111 0 R 112 0 R]
>>
endobj

212 0 obj
<< /Type /StructElem
/S /LI % List item for "2. Ice-skating"
/P 301 0 R
/K [121 0 R 122 0 R]
>>
endobj

213 0 obj
<< /Type /StructElem
/S /LI % List item for "3. Skiing"
/P 301 0 R
/K [131 0 R 132 0 R]
>>
endobj

400 0 obj
<< /Type /StructElem
/S /L % Top-level structure element in the list hierarchy
/K [201 0 R 211 0 R 212 0 R 213 0 R]
>>
endobj
Resources
Resources are for information purposes only, no endorsement implied.
Section 14.8.4.3.3 (List Elements) in
PDF
1.7 (ISO 32000-1)
PDF and Accessibility
Related Techniques
G115: Using semantic elements to mark up structure
Tests
Procedure
For a list in a PDF document, verify in one of the following
ways:
Read the PDF document with a screen reader, listening to hear
that list is read correctly when reading the content line-by-line.
Use a tool that is capable of showing lists to open the PDF
document and view the list to check that it is correctly structured.
Inspect the tag tree to verify that the list is structured
according to the PDF specification.
Use a tool that exposes the document through the accessibility
API and verify that the list is correctly structured.
Expected Results
#1 is true
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF22: Indicating when user input falls outside the required format or
values in PDF forms
Applicability
Tagged PDF documents
This technique relates to:
Success Criterion 3.3.1 (Error Identification)
How to Meet 3.3.1 (Error Identification)
Understanding Success Criterion 3.3.1 (Error Identification)
Success Criterion 3.3.3 (Error Suggestion)
How to Meet 3.3.3 (Error Suggestion)
Understanding Success Criterion 3.3.3 (Error Suggestion)
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF22
. Also see
PDF Technology Notes
Description
The objective of this technique is to notify the user when user
input to a field that requires a specific, required format (e.g.,
date fields) is not submitted in that format.
If the required format is not used, an alert dialog describes the
nature of the error in text. This may be accomplished through scripting
created by the author (see, for example,
SCR18:
Providing client-side validation and alert
). User agents, such
as Adobe LiveCycle can provide automatic alerts (as described in
the examples below).
Note:
Once the user dismisses the alert dialog,
it may be helpful if the script positions the keyboard focus on
the field where the error occurred, although some users may expect
the focus to remain on the last control focused prior to the alert
appearing. Authors should exercise care to ensure that any movement
of the focus will be expected. For example, if the alert announces
an error in a phone number format, positioning the focus on the
phone number field when the alert is dismissed can be regarded as
helpful and expected. In some cases, however, this may not be possible.
If multiple input errors occur on the page, an alternative approach
to error notification should be implemented.
Ensuring that users are aware an error has occurred, can determine
what is wrong, and can correct it are key to software usability
and accessibility. Meeting this objective helps ensure that all
users can complete for-based transactions with ease and confidence.
Labels for required formats in form controls
It is also important that users are aware that an error
may
occur.
You can incorporate this information in labels; for example, "Date
(MM/DD/YYYY)." See
PDF10: Providing labels for interactive form controls in PDF documents
Examples
Example 1: Providing validation for an input field format using
Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
Many fields -- telephone number, postal code, date -- must have
data entered in a specific format or pattern.
Access the context menu for the form control that requires
a specific format.
Select Properties...
In the Format tab, select the Format Category (in this case,
Date). The Date Options appear.
Select the format for this form control (in this case, mm/dd/yyyy).
In the General tab, specify "Date (mm/dd/yyyy)" for
the Name and Tooltip for the control.
When a user types a recognized date format, it is converted automatically
to the specified format. If the date format or value is not recognized,
an error alert appears and provides further information, as shown
in the image below.
This example is shown in operation in the
working example of Required Fields in Acrobat
Example 2: Providing validation for an input field format using
Adobe LiveCycle Designer ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are
other software tools that perform similar functions. See the list
of other software tools in
PDF Authoring Tools that Provide Accessibility Support
Select the form control that has a required format.
In the Object palette, click the Validation Pattern... button.
Because this is a date field the Patterns-Date Field dialog
appears. Select the pattern or format you want users to enter.
Then click OK.
In the Object palette, use the Validation Pattern Message box
to type a warning message. Be sure to include the required pattern.
This message appears when a user tries to submit the form using
an invalid date format.
This example is shown in operation in the
working example of Required Fields in LiveCycle Designer
Example 3: Validating a required date format in a PDF form using
JavaScript using Adobe Acrobat Pro 9
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
The following JavaScript code illustrates the use of a script to
validate form fields, in this case, a date field. To add this script
to the form field, open the Text Field Properties dialog, as shown
in Example 1, and select Edit in the Validate tab:
// JavaScript code for date mask format MM/DD/YYYY
var re = /^[mdy0-9]{2}\/[mdy0-9]{2}\/[mdy0-9]{4}$/
//Allow blank space in field
if (event.value !="") {
if (re.test(event.value) == false) {
app.alert ({
cTitle: "Incorrect Format",
cMsg: "Please enter date using mm/dd/yyyy format"
});
Resources
Resources are for information purposes only, no endorsement implied.
JavaScript
for Acrobat
Related Techniques
G89: Providing expected data format and example
SCR18: Providing client-side validation and alert
PDF23: Providing interactive form controls in PDF documents
PDF10: Providing labels for interactive form controls in PDF documents
PDF5: Indicating required form controls in PDF forms
Tests
Procedure
For each form field that requires specific input, verify that validation
information and instructions are provided by applying the following:
Check that the format or value that is required is indicated
in the form control's label.
Use an erroneous format or value and move off the field: make
sure that an alert describing the error is provided.
Expected Results
#1 and #2 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
PDF23: Providing interactive form controls in PDF documents
Applicability
Tagged PDF documents with forms.
PDF forms created using Adobe LiveCycle Designer.
This technique relates to:
Success Criterion 2.1.1 (Keyboard)
How to Meet 2.1.1 (Keyboard)
Understanding Success Criterion 2.1.1 (Keyboard)
Success Criterion 2.1.3 (Keyboard (No Exception))
How to Meet 2.1.3 (Keyboard (No Exception))
Understanding Success Criterion 2.1.3 (Keyboard (No Exception))
User Agent and Assistive Technology Support Notes
See
User Agent Support Notes for PDF23
. Also see
PDF Technology Notes
Description
The objective of this technique is to ensure that interactive form
controls in PDF documents allow keyboard operation. Interactive
PDF forms are generally created using a tool for authoring PDF.
Form controls are implemented in PDF documents either as described
in Section 12.7 (Interactive Forms) of
PDF
1.7 (ISO 32000-1)
or as described in the
Adobe
XML Forms Architecture (XFA)
The types of PDF form controls are: text input field, check box,
radio button, combo box, list box, and button.
Form controls allow users to interact with a PDF document by filling
in information or indicating choices, which can then be submitted
for processing. Users who rely on keyboard access must be able to
recognize and understand the form fields, make selections, and provide
input to complete the forms, and submit the form, just as sighted
users can.
Interactive form controls can be provided for forms created by
converting a scanned paper form to tagged PDF or by creating a form
in an authoring application such as Microsoft Word or Open Office
and converting it to tagged PDF.
However, documents created by authoring applications that provide
form design features might not fully retain their fillable form
fields on conversion to PDF. Complex forms in particular may not
have properly converted form fields and labels when tagged in conversion.
Using Adobe Acrobat Pro with forms in converted documents, you
can ensure that form fields are keyboard accessible and usable by:
Opening tagged PDF documents with form fields and creating
interactive PDF form elements with the Run Form Fields Recognition
tool.
Modifying fillable form fields, or adding form fields, using
Adobe Acrobat Pro or Adobe LiveCycle Designer.
Using Adobe LiveCycle Designer, you can create forms from scratch.
Examples
Example 1: Adding interactive controls to existing forms in PDF
documents using Adobe Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
If you have a form in a tagged PDF document (created by scanning
a paper form or using an authoring tool to generate tagged PDF),
you can use Adobe Acrobat Pro to make the form elements keyboard
accessible in the same page locations as the static form.
Use Advanced > Accessibility > Run Form Field Recognition
to automatically detect form fields and make them fillable.
The following image shows the Run Form Field Recognition tool is
selected to detect form fields in a document converted to tagged
PDF.
The following image shows the resulting form fields after the
Run Form Recognition tool is run.
This example is shown in operation in the
working example of Interactive Controls in Acrobat
Example 2: Adding form controls in PDF documents using Adobe Acrobat
9 Pro
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
You can add keyboard accessible form controls to your form as follows:
Forms > Add or Edit Fields... This puts the form in Form
Editing mode.
Open the Add New Field menu on the upper left, and select a
form field to add. The image below shows the menu of fields.
The following image shows a checkbox added to the form in Example
1.
This example is shown in operation in the
working example of Interactive Controls in LiveCycle Designer
Example 3: Editing form controls in PDF documents using Adobe
Acrobat 9 Pro
This example is shown with Adobe Acrobat Pro. There are other software
tools that perform similar functions. See the list of other software
tools in
PDF Authoring Tools that Provide Accessibility Support
To edit fields, select the context menu for the field and select
Properties... The properties menu for that form field lets you modify
it, as shown in the following image.
Note:
The tooltip is not keyboard accessible but will be screen-reader
accessible: see
PDF12: Providing name, role, value information for form fields in PDF documents
Example 4: Creating new interactive forms with Adobe LiveCycle
Designer ES 8.2.1
This example is shown with Adobe LiveCycle Designer. There are
other software tools that perform similar functions. See the list
of other software tools in
PDF Authoring Tools that Provide Accessibility Support
You can use Adobe LiveCycle Designer to create new forms. In addition
to invoking this standalone tool from the Windows Start menu, you
can invoke it in Adobe Acrobat Pro:
Forms > Start Form Wizard...
Select the No Existing Form radio button, as shown in the following
image.
Clicking Next invokes LiveCycle Designer and the first page of
the New Form Assistant. as shown in the following image.
When you invoke LiveCycle Designer from the Windows Start menu,
the Form Wizard is available from File > New...
The New Form Assistant creates a blank form. Use the Object Library
in the right pane to select form controls.
You can also use LiveCycle Designer to create forms based on commonly
used forms templates.
Invoke the Template Assistant wizard from the New pulldown:
Select Forms and then select an appropriate type of form. Then,
you can personalize the form by swapping out placeholder text,
graphics, form fields, and properties with custom objects that
you provide or define.
Example 5: Adding a text field in a PDF document using the /Tx
field type
The following code fragment illustrates code that is typical for
a simple text field such as shown in Examples 1 and 2. This is typically
accomplished by an authoring tool.
<< /AP -dict-
/DA /Helv 0 Tf 0 g
/DR -dict-
/F 0x4
/FT Tx % FT key set to Tx for Text Field
/P -dict-
/Rect -array-
/StructParent 0x1
/Subtype Widget
/T Date you are available % Partial field name Date
/TU Date you are available: use mm/dd/yyyy format % TU tool tip value serves as short description
/Type Annot
/V Pat Jones
>>
...

BT
/P <>BDC
/CS0 cs 0 scn
/TT0 1 Tf
-0.001 Tc 0.003 Tw 11.04 0 0 11.04 72 709.56 Tm
[(P)-6(le)-3(as)10(e)-3( )11(P)-6(rin)2(t)-3( Y)8(o)-7(u)2(r N)4(a)11(m)-6(e)]TJ
0 Tc 0 Tw 9.533 0 Td
( )Tj
-0.004 Tc 0.004 Tw 0.217 0 Td
[(\()-5(R)-4(e)5(q)-1(u)-1(i)-3(r)-3(e)-6(d)-1(\))]TJ
EMC
/P <>BDC
0 Tc 0 Tw 4.283 0 Td
[( )-2( )]TJ
EMC
/ArtifactSpan <>BDC
0.002 Tc -0.002 Tw 0.456 0 Td
[(__)11(___)11(___)11(___)11(___)11(_)11(____)11(___)11(___)11(__)]TJ
0 Tc 0 Tw 13.391 0 Td
( )Tj
EMC
ET

Resources
Resources are for information purposes only, no endorsement implied.
Section 12.7 (Interactive Forms) in
PDF
1.7 (ISO 32000-1)
Adobe
XML Forms Architecture (XFA)
Related Techniques
G202: Ensuring keyboard control for all functionality
PDF3: Ensuring correct tab and reading order in PDF documents
PDF12: Providing name, role, value information for form fields in PDF documents
PDF15: Providing submit buttons with the submit-form action in PDF forms
Tests
Procedure
For each form control, verify that it is properly implemented
by tabbing to each form control and checking that it can be activated
or that its value can be changed from the keyboard.
Expected Results
#1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
CSS1
"Cascading Style Sheets, level 1," B. Bos, H. Wium Lie, eds., W3C Recommendation 17 Dec 1996, revised 11 Jan 1999. Available at
CSS2
"Cascading Style Sheets, level 2," B. Bos, H. Wium Lie, C. Lilley, and I. Jacobs, eds., W3C Recommendation 12 May 1998. Available at
CSS21
"Cascading Style Sheets, level 2 revision 1," B. Bos, T. Çelik, I. Hickson, H. Wium Lie, eds., W3C Candidate Recommendation 25 February 2004. Available at:
CSS3
[CSS 2.1 and CSS 3] Roadmap
, CSS WG's table of modules and publication dates.
HTML4
"HTML 4.01 Specification," D. Raggett, A. Le Hors, I. Jacobs, eds., W3C Recommendation 24 December 1999. Available at
ISO32000
"Document management - Portable document format - Part 1: PDF 1.7", ISO/TC 171/SC 2. ISO. Available at
. ISO-approved copy available at:
WCAG20
"Web Content Accessibility Guidelines 2.0," B. Caldwell, M. Cooper, L. Guarino Reid, and G. Vanderheiden, eds., W3C Working Draft 11 December 2007. This W3C Working Draft is available at
. The latest version of WCAG 2.0 is available at
XHTML1
"XHTML 1.0 The Extensible HyperText Markup Language (Second Edition)," S. Pemberton, et al., W3C Recommendation 26 January 2000, revised 1 August 2002. Available at:
This Web page is part of
Techniques for WCAG 2.0
. The entire document is also available as a
single HTML file
. See the
The WCAG 2.0 Documents
for an explanation of how this document fits in with other Web Content Accessibility Guidelines (WCAG) 2.0 documents.
W3C
MIT
ERCIM
Keio
Beihang
). W3C
liability
trademark
and
document use
rules apply.