MetaExtensions - WHATWG Wiki

MetaExtensions - WHATWG Wiki
A user account is required in order to edit this wiki, but we've had to disable public user registrations due to spam.
To request an account, ask an autoconfirmed user on
Chat
(such as one of
these permanent autoconfirmed members
).
MetaExtensions
From WHATWG Wiki
Jump to navigation
Jump to search
This page lists extension values for the name="" attribute of the HTML element. You may add your own values to this list.
For assistance in preparing a specification, see the
specification editing
category and the
Bikeshed
documentation.
If the specification is ready, we ask that you:
Avoid redundancy.
If someone has already defined a name that does roughly what you want, please reuse it.
Be sure to include
all
the items
outlined in the spec
including a link to a specification
that specifies the keyword
as an HTML meta keyword
. If a proposal lacks a specification and a version in a complete specification exists, the latter is to be preferred.
Alphabetize by keyword
, without regard for case, in any table. Sort nonalphanumerics by ASCII value.
Not reserve namespaces.
Instead, register individual names (known as enumerated values although you don't have to number them).
URL-valued attributes must not be added to this page as meta names but should be registered as
rel keywords
instead.
Contents
Meta Name Extensions
Proposals That Don't Meet the Requirements For a Registration
Failed Proposals
Meta Name Extensions
Keyword
Brief description
Link to specification
Synonyms
Status
AGLSTERMS.accessibility
A statement indicating the accessibility characteristics of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.accessMode
Perceptual mode for the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.act
A specific piece of legislation which requires or drives the creation or provision of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.aggregationLevel
The level of aggregation of the described resource - an 'item' or a 'collection'.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.allow-search
A specific piece of legislation which requires or drives the creation or provision of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.availability
How the resource can be obtained or accessed, or contact information. Primarily used for offline resources to provide information on how to obtain physical access to the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.case
A specific piece of case law which requires or drives the creation or provision of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.category
The generic type of the resource being described - a 'service', 'document' or 'agency'.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.dateLicensed
Date a license was applied or became effective.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.documentType
The form of the described resource where the value of category is‘document’. Document is used in its widest sense and includes resources such as text, images, sound files and software.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.function
The business function to which the resource relates. Functions are the major units of activity which organisations pursue in order to meet the mission and goals of the organisation.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.isBasedOn
A related resource of which the described resource is a performance, production, derivation, translation or interpretation.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.isBasisFor
A related resource that is a performance, production, derivation, translation or interpretation of the described resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.jurisdiction
The name of the political/administrative entity covered by the described resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.mandate
A specific legal instrument which requires or drives the creation or provision of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.protectiveMarking
A protective marking applied to the described resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.regulation
A specific regulation which requires or drives the creation or provision of the resource.
AGLS Metadata Usage Guide
Proposal
AGLSTERMS.serviceType
The form of the described resource where the value of category is ‘service'.
AGLS Metadata Usage Guide
Proposal
alexaverifyid
Used to verify ownership of Alexa Search
Alexa FAQ About this meta attribute Reference
Proposal
apple-itunes-app
Promoting Apps with Smart App Banners
Safari Web Content Guide
Proposal
apple-mobile-web-app-capable
Sets whether a web application runs in full-screen mode.
Apple Safari HTML Reference
mobile-web-app-capable (also could maybe be assumed when
application-name
is set?)
Proposal
apple-mobile-web-app-status-bar-style
Sets the style of the status bar for a web application.
Apple Safari HTML Reference
Proposal
apple-mobile-web-app-title
Sets the title of the application when added to the homescreen on iOS6+
Unofficial Documentation of apple-mobile-web-app-title
- Read more about Apple's web-app's at
Apple Safari HTML Reference
Proposal
apple-touch-fullscreen
forces iPhone Fullscreen mode, if added to home screen. Not needed anymore.
No specification yet
Proposal
application-name
For Windows 7: "[D]efines the name of the Pinned site application instance. This is the name that appears in a tooltip when hovering over the Pinned site button on the Windows 7 taskbar. The application name is also appended to the window title of the Pinned site application instance." Although the documentation refers to an application, it gives an example of writing this metadata for HTML. Indeed, this name must not be used except in a Web application, according to HTML Living Standard and HTML 5.1.
Declaring Pinned Site Metadata (Microsoft Developer Network)
Proposed
application-url
Start URL of web apps in Google Chrome
The "application-url" meta tag can be used to specify the start URL of pinned web apps in Google Chrome.

Google Chrome Webmaster FAQ
Chromium issue response
Proposal
appstore:bundle_id
Application bundle identifier or package identifier, used to identify applications on platforms and within some app stores. Usage:

IAB Tech Lab app-ads.txt documentation: https://iabtechlab.com/ads-txt/
Proposal
appstore:developer_url
The consumer-visible URL published as developer contact details within an app store listing for an app. Usage:

IAB Tech Lab app-ads.txt documentation: https://iabtechlab.com/ads-txt/
Proposal
appstore:store_id
An app store specific identifier representing the stock keeping unit (SKU) or another identifier used to locate the app within the store. Usage:

IAB Tech Lab app-ads.txt documentation: https://iabtechlab.com/ads-txt/
Proposal
audience
Categorize the principal intended audience for the page, generally with a controlled vocabulary.
Google uses this tag:
Custom Search Help
, as accessed Jan. 8, 2016.
BrittleBit.org spec
Proposal
bitcoin
A bitcoin-address
Short documentation (unofficial):
FrontendNetworks unofficial documentation for bitcoin-metatag
, more informations about the Bitcoin-adress:
Bitcoin wiki
Proposal
blazerr-secure
Decides whether connect via a secure connection or not to JokeNetwork's Blazerr-System. Synonym to blazerr-ssl, but only for old browsers such as Internet Explorer 7.
Usage:

JokeNetwork's Blazerr Documentation
Proposal
blazerr-seo
Checks whether Blazerr SEO has been used or not. It contains the user-id and the SEO Version.
Usage:

0001 is an example for a user id, v0.7 identifies which version of SEO is used (In this case version Beta 7 / 0.7). If you're using Blazerr SEO, you have to include this meta-tag. Otherwise the tool will not work.
JokeNetwork's Blazerr Documentation
Proposal
blazerr-ssl
Decides whether connect via a secure connection or not to JokeNetwork's Blazerr-System. Similar to blazerr-secure.
Usage:

JokeNetwork's Blazerr Documentation
blazerr-secure is partial synonym (see that entry)
Proposal
blazerr-support-id-noncookies
Used to identify users for JokeNetwork's Blazerr Support-System without a cookie. Deprecated.
JokeNetwork's Blazerr Documentation
Proposal
blazerr-support-identifier
Used to identify users for JokeNetwork's Blazerr Support-System along with a cookie. The verification of a user without the use of cookies can be obtained with the deprecated meta tag
blazerr-support-id-noncookies
JokeNetwork's Blazerr Documentation
Proposal
bug.blocked
Bugzilla dependency tree to which the
bug-creation script will add a link.
Embedded documentation
Proposal
bug.comment
Bugzilla comment used by the
bug-creation script.
Embedded documentation
Proposal
bug.component
Bugzilla component against which the
bug-creation script will create a new bug.
Embedded documentation
Proposal
bug.product
Bugzilla product against which the
bug-creation script will create a new bug.
Embedded documentation
Proposal
bug.short_desc
Bugzilla short description used by the
bug-creation script.
Embedded documentation
Proposal
cfia.gdr.activity
Canadian Food Inspection Agency Guidance Document Repository Page Activity
Coming soon at
CFIA website
Proposal
cfia.gdr.commodity
Canadian Food Inspection Agency Guidance Document Repository Page Commodity
Coming soon at
CFIA website
Proposal
cfia.gdr.include
Canadian Food Inspection Agency Guidance Document Repository Page
Coming soon at
CFIA website
Proposal
cfia.gdr.program
Canadian Food Inspection Agency Guidance Document Repository Page Program
Coming soon at
CFIA website
Proposal
citation_author
The name of an author of an academic paper
Google Scholar indexing documentation
Proposal
citation_author_email
The email address of the preceding author (identified using citation_author) of an academic paper
Proposal
citation_author_institution
The name of an institution to which the preceding author (identified using citation_author) of an academic paper is affiliated
Proposal
citation_conference_title
The title of the conference at which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_date
The publication date of an academic paper
Proposal
citation_dissertation_institution
The name of the institution which published an academic dissertation
Google Scholar indexing documentation
Proposal
citation_doi
The Digital Object Identifier of an academic paper
Proposal
citation_firstpage
The first page of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_fulltext_html_url
The URL of the full text HTML version of an academic paper
Proposal
citation_isbn
The ISBN of the book in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_issn
The ISSN of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_issue
The issue of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_journal_abbrev
The abbreviated title of the journal in which an academic paper is published
Proposal
citation_journal_title
The title of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_keywords
A semicolon-separated list of keywords associated with an academic paper
Proposal
citation_language
The language in which an academic paper is written, as an ISO 639-1 two-letter code
Proposal
citation_lastpage
The last page of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
citation_pdf_url
The URL of a PDF version of an academic paper
Google Scholar indexing documentation
Proposal
citation_publication_date
The publication date of an academic paper
Google Scholar indexing documentation
Proposal
citation_publisher
The name of the publisher of an academic paper
The
spec
(as accessed 11-26-17) omits this meta name but refers to the meta name DC.publisher (see that on this page).
Proposal
citation_technical_report_institution
The name of the institution which published an academic technical report or preprint
Google Scholar indexing documentation
Proposal
citation_technical_report_number
The identification number of an academic technical report or preprint
Google Scholar indexing documentation
Proposal
citation_title
The title of an academic paper
Google Scholar indexing documentation
Proposal
citation_volume
The volume of the journal in which an academic paper is published
Google Scholar indexing documentation
Proposal
collection
To replace the obsolete dc:collection. A collection is described as a group, an aggregation of topics Used to describe the top-level content of XHTML documents. These appear in your META tags showing a group of subject. Website Taxonomy improve classification for search engine analysis and semantic communication with a description language content.


[1]
Proposal
contact
Defines the vendor's contact information by way of a phone-number (such as the customer support number), an e-mail ID (such as the customer support mail ID) or a physical address (such as the office address or billing address).
Usage:

or in case of multiple entries:

The content attribute is a space separated string containing the phone-number followed by the e-mail ID and then the address (specified within quotes).
For specifying multiple entries a semi-colon separated list of name: value pairs can be defined. The name can be any descriptive tag identifying the given location.
Valid phone numbers and mail IDs should be provided by the vendor. The address can either be a string specified within quotes or the latitude and longtitude coordinates.
Documentation
Proposal
creator
Identify the creator of the page’s content, the content generally being the principal part of what info is rendered for website visitors.
BrittleBit.org spec
Proposal
csrf-param
Cross-site request forgery protection parameter for Ruby on Rails
Rails API
Proposal
csrf-token
Cross-site request forgery protection token for Ruby on Rails
Rails API
Proposal
da_anonymiseIP
Defines anonymiseIP parameter for Decibel Insight
Documentation
Proposal
da_contactCompany
Defines the contactCompany of the page for Decibel Insight
Documentation
Proposal
da_contactEmail
Defines the contactEmail of the page for Decibel Insight
Documentation
Proposal
da_contactFirstName
Defines the contactFirstName of the page for Decibel Insight
Documentation
Proposal
da_contactLastName
Defines the contactLastName of the page for Decibel Insight
Documentation
Proposal
da_contactName
Defines the contactName of the page for Decibel Insight
Documentation
Proposal
da_contactTelephone
Defines the contactTelephone of the page for Decibel Insight
Documentation
Proposal
da_conversionCurrency
Defines the conversionCurrency of the page for Decibel Insight
Documentation
Proposal
da_conversionId
Defines the conversionId of the page for Decibel Insight
Documentation
Proposal
da_conversionValue
Defines the conversionValue of the page for Decibel Insight
Documentation
Proposal
da_goalCurrency
Defines the goalCurrency of the page for Decibel Insight
Documentation
Proposal
da_goalId
Defines the goalId of the page for Decibel Insight
Documentation
Proposal
da_goalValue
Defines the goalValue of the page for Decibel Insight
Documentation
Proposal
da_interactionSelector
Defines the interactionSelector parameter for Decibel Insight
Documentation
Proposal
da_pageRole
Defines the role of the page for Decibel Insight
Documentation
Proposal
da_pageTaxonomy
Defines the taxonomy of the page for Decibel Insight
Documentation
Proposal
da_pageTitle
Defines the pageTitle of the page for Decibel Insight
Documentation
Proposal
da_pageVersion
Defines the pageVersion of the page for Decibel Insight
Documentation
Proposal
da_sessionId
Defines the sessionId parameter for Decibel Insight
Documentation
Proposal
da_userId
Defines the userId parameter for Decibel Insight
Documentation
Proposal
dc.created
Date of creation of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.creator
An entity primarily responsible for making the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.date.issued
Date of publication for Google News. The format of the content is YYYY-MM-DD or YYYY-MM-DDThh:mm:ssTZD.
It must be accompanied by a

element
Google News documentation
dcterms.issued
(former

no longer considered due to the abort of
@pubdate
Proposal
dc.dateCopyrighted
Date of copyright.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.dateSubmitted
Date of submission of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.description
An account of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.language
A language of the resource. Recommended best practice is to use a controlled vocabulary such as RFC 4646 [RFC4646].
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Redundant with the
lang
attribute on the
html
element. (Browsers pay attention to the
lang
attribute but not
dc.language
Proposal
dc.license
A legal document giving official permission to do something with the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.mediator
An entity that mediates access to the resource and for whom the resource is intended or useful.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.medium
The material or physical carrier of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.modified
Date on which the resource was changed.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.provenance
A statement of any changes in ownership and custody of the resource since its creation that are significant for its authenticity, integrity, and interpretation.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.publisher
An entity responsible for making the resource available.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.references
A related resource that is referenced, cited, or otherwise pointed to by the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.temporal
Temporal characteristics of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.title
A name given to the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.type
The nature or genre of the resource. Recommended best practice is to use a controlled vocabulary such as the DCMI Type Vocabulary [DCMITYPE].
To describe the file format, physical medium, or dimensions of the resource, use the Format element.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dc.valid
Date (often a range) of validity of a resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
DCS.dcssta
Error page parameter
This defines an error code web page so that Webtrends can identify it as a non-success page. Generally used to identify pages that contain 400 and 500 series return codes. As a result, Webtrends excludes these pages from its standard "Pages" report, to instead populate its standard "errors" report.
Example:

Webtrends Parameters
Proposal
dcterms.abstract
A summary of the resource.
It must be accompanied by a

element.
DCMI
Metadata Terms] mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements

Proposal
dcterms.accessRights
Information about who can access the resource or an indication of its security status.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.accrualMethod
The method by which items are added to a collection.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.accrualPeriodicity
The frequency with which items are added to a collection.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.accrualPolicy
The policy governing the addition of items to a collection.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.alternative
An alternative name for the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.audience
A class of entity for whom the resource is intended or useful.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.available
Date (often a range) that the resource became or will become available.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.bibliographicCitation
A bibliographic reference for the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML attribute
cite
Proposal
dcterms.collection
An aggregation of resources.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.conformsTo
An established standard to which the described resource conforms.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.contributor
An entity responsible for making contributions to the content of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.coverage
The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.created
Date of creation of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.creator
An entity primarily responsible for making the resource. Examples of a Creator include a person, an organization, or a service.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
In some cases redundant with the HTML built-in keyword
author
Proposal
dcterms.date
A point or period of time associated with an event in the lifecycle of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.dateAccepted
Date of acceptance of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.dateCopyrighted
Date of copyright.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.dateSubmitted
Date of submission of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.description
An account of the resource. Description may include but is not limited to: an abstract, a table of contents, a graphical representation, or a free-text account of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
HTML built-in keyword
description
Proposal
dcterms.educationLevel
A class of entity, defined in terms of progression through an educational or training context, for which the described resource is intended.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.extent
The size or duration of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.format
The file format, physical medium, or dimensions of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
To be limited to dimensions information. File format for the document is to be determined by server. Linked resources can be described by
type
attribute.
Proposal
dcterms.hasFormat
A related resource that is substantially the same as the pre-existing described resource, but in another format.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.hasPart
A related resource that is included either physically or logically in the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.hasVersion
A related resource that is a version, edition, or adaptation of the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.identifier
An unambiguous reference to the resource within a given context.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.instructionalMethod
A process used to engender knowledge, attitudes and skills, that the described resource is designed to support.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.isFormatOf
A related resource that is substantially the same as the described resource, but in another format.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.isPartOf
A related resource in which the described resource is physically or logically included.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.isReferencedBy
A related resource that references, cites, or otherwise points to the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.isReplacedBy
A related resource that supplants, displaces, or supersedes the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.isRequiredBy
A related resource that requires the described resource to support its function, delivery, or coherence.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.issued
Date of formal issuance (e.g., publication) of the resource. (DC doesn't spec a date format but the established practice is YYYY-MM-DD.)
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
(former

no longer considered due to the abort of
@pubdate
Proposal
dcterms.isVersionOf
A related resource of which the described resource is a version, edition, or adaptation.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.language
A language of the resource. Recommended best practice is to use a controlled vocabulary such as RFC 4646 [RFC4646].
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Redundant with the
lang
attribute on the
html
element. (Browsers pay attention to the
lang
attribute but not
dcterms.language
Proposal
dcterms.license
A legal document giving official permission to do something with the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML

element with the keyword
"license"
as value of the
rel
attribute.
Proposal
dcterms.mediator
An entity that mediates access to the resource and for whom the resource is intended or useful.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.medium
The material or physical carrier of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.modified
Date on which the resource was changed. (DC doesn't spec a date format but the established practice is YYYY-MM-DD.)
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.provenance
A statement for any changes in ownership and custody of the resource since its creation that are significant for its authenticity, integrity, and interpretation.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.publisher
An entity responsible for making the resource available.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
publisher
Proposal
dcterms.references
A related resource that is referenced, cited, or otherwise pointed to by the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
cite
attribute on specific quotes, if any.
Proposal
dcterms.relation
A related resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
If the relation comes from an internal reference or quote,
dcterms.references
should be preferred.
Proposal
dcterms.replaces
A related resource that is supplanted, displaced, or superseded by the described resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
Proposal
dcterms.requires
A related resource that is required by the described resource to support its function, delivery, or coherence.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.rights
Information about rights held in and over the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML

element with the keyword
"license"
as value of the
rel
attribute, if referring to a legal license format.
Proposal
dcterms.rightsHolder
A person or organization owning or managing rights over the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.source
A related resource from which the described resource is derived.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
The HTML link type keyword "alternate" used with "link" element:
rel="alternate" href="URI of related resource"
if documents are different versions. Otherwise,
cite
attribute.
Proposal
dcterms.spatial
Spatial characteristics of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
geographic-coverage
Proposal
dcterms.subject
The topic of the resource.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
HTML built-in keywords
description
or
keywords
Proposal
dcterms.tableOfContents
A list of subunits of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
HTML built-in keywords
description
or
keywords
. Otherwise, a
details-summary
model which would provide user-readable information.
Proposal
dcterms.temporal
Temporal characteristics of the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.title
A name given to the resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
HTML built-in element
title
(not to be confused with
@title
attributes specific to each element)
Proposal
dcterms.type
The nature or genre of the resource.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
dcterms.valid
Date (often a range) of validity of a resource.
It must be accompanied by a

element.
DCMI Metadata Terms
mapped according to
Expressing Dublin Core metadata using HTML/XHTML meta and link elements
Proposal
detectify-verification
Used by the Detectify web vulnerability scanner as a domain verification key. The Detectify service will only consider the domain authenticated if it contains the "detectify-verification" meta tag, with the content set according to a per-customer token.
Documentation
Proposal
designer
Credits the designer(s) responsible for the visual presentation of a website.
Documentation
Proposal
entity
Allows for definitions of XML-style entities for substitution of references (defined as specially-named elements (e.g., use of data element and/or data-* attribute) or script tags) via inclusion of a JavaScript library. Library also supports inclusion of additional meta element entity definitions via iframe documents.
Documentation
Proposal
EssayDirectory
Defines a custom description of websites listed in EssayDirectory.
Example:

Documentation
Proposal
fdse-description
Tag used by FDSE search software, allows different description to be displayed in fdse results to that shown in description
[2]
Proposal
fdse-index-as
Tag used by FDSE search software, allows FDSE to index a page as url described here
[3]
Proposal
fdse-keywords
Tag used by FDSE search software, allows different keywords to be used by FDSE to keywords tag
[4]
Proposal
fdse-refresh
Tag used by FDSE search software, allows FDSE to ignore refresh meta tags
[5]
Proposal
fdse-robots
Tag used by FDSE search software, allows different robots instructions to be sent to FDSE than that sent to other search engines eg: index no index pages for local search
[6]
Proposal
FLBlogAuthor
Depicts whether author of the blog is lawfirm or FL author
FL Meta Names documentation
Proposal
format-detection
Enables or disables automatic detection of possible phone numbers in a webpage in Safari on iOS.
Apple Safari HTML Reference
Proposal
format-print
Store print media requirements for a page so a user agent can alert a user to unusual needs, such as special paper, before printing is to begin.
BrittleBit.org spec
Proposal
fragment
Opts a webpage into the AJAX crawling scheme when it does not have a "#!" URL. The only valid content value is "!".

Google Crawable AJAX Specification
Proposal
FSDateCreation
Mentions the date when this web page was created
FL Meta Names documentation
Proposal
FSDatePublish
Mentions the date when this web page was created
FL Meta Names documentation
Proposal
FSFLContent
Informs the Publisher tool whether this page contains any content or not. Valid values yes or no
FL Meta Names documentation
Proposal
FSLanguage
Language of the content in the page. Example: US English or UK English, etc
FL Meta Names documentation
Proposal
FSOnSitemap
Whether the page is accessible via the Sitemap link in the firmsite
FL Meta Names documentation
Proposal
FSPageDescription
Description of the content of page
FL Meta Names documentation
Proposal
FSPageName
Name of the page within a Findlaw firmsite
FL Meta Names documentation
Proposal
FSSearchable
This tag mentions whether a certain page can be searched or not
FL Meta Names documentation
Proposal
FSSection
Depicts whether a page is a Section Page or simple page. Section pages can have links to other pages
FL Meta Names documentation
Proposal
FSWritertoolPageType
Page Type of a page in the firmsite. Page Type values help the Publisher toold in page creation
FL Meta Names documentation
Proposal
gcterms.topicTaxonomy
Organize resources specifically for taxonomy-based topical browse or search structures on websites (ie: breadcrumbs / website information architecture).
[7]
Government of Canada, Web Content Management System Metadata Application Profile.
Proposal
geo.a1
National subdivision (state, canton, region, province, prefecture) of civil address to which the page is related. For resources within the US and Canada, corresponds to the common 2-character State/Province codes.

IETF Draft
GeoTags.com
RFC 4776
Proposal
geo.a2
County, parish, gun (JP), district (IN) of civil address to which the page is related.

IETF Draft
GeoTags.com
RFC 4776
Proposal
geo.a3
City, township, shi (JP) of civil address to which the page is related.

IETF Draft
GeoTags.com
RFC 4776
Proposal
geo.country
Case-insensitive ISO 3166-1 alpha-2 code of a country to which the page is related.

IETF Draft
GeoTags.com
ISO-3166-2
Proposal
geo.lmk
A landmark or vanity address to which the page is related.

IETF Draft
GeoTags.com
Proposal
geo.placename
Superseded by geo.lmk. Name of geographic place to which the page is related.

IETF Draft
GeoTags.com
Proposal
geo.position
Geographic position to which the page is related.

Like icbm except for value syntax.
IETF Draft (expired)
GeoTags.com
Proposal
geo.region
Superseded by either geo.country alone or geo.country plus geo.a1. Name of geographic region to which the page is related. Content is specified by ISO-3166.

IETF Draft
GeoTags.com
ISO-3166
Proposal
globrix.bathrooms
Globrix property information: Number of bathrooms the property has
FAQ About the Globrix meta tags.
Proposal
globrix.bedrooms
Globrix property information: Number of bedrooms the property has
FAQ About the Globrix meta tags.
Proposal
globrix.condition
Globrix property information: Condition of the property e.g. 'renovated'
FAQ About the Globrix meta tags.
Proposal
globrix.features
Globrix property information: Features of the property e.g. 'double glazing'
FAQ About the Globrix meta tags.
Proposal
globrix.instruction
Globrix property information: Property to Buy or Rent
FAQ About the Globrix meta tags.
Proposal
globrix.latitude
Globrix property information: The latitude of the property
FAQ About the Globrix meta tags.
Proposal
globrix.longitude
Globrix property information: The longitude of the property
FAQ About the Globrix meta tags.
Proposal
globrix.outsidespace
Globrix property information: External features of the property e.g. 'garden'
FAQ About the Globrix meta tags.
Proposal
globrix.parking
Globrix property information: Parking available for property e.g. 'parking for 2 cars'
FAQ About the Globrix meta tags.
Proposal
globrix.period
Globrix property information: Period of the property e.g. 'victorian terrace'
FAQ About the Globrix meta tags.
Proposal
globrix.poa
Globrix property information: If the property price is only available on application
FAQ About the Globrix meta tags.
Proposal
globrix.postcode
Globrix property information: Postcode of the property
FAQ About the Globrix meta tags.
Proposal
globrix.price
Globrix property information: Price for the property
FAQ About the Globrix meta tags.
Proposal
globrix.priceproximity
Globrix property information: The region of the attached price e.g. 'guide price of'
FAQ About the Globrix meta tags.
Proposal
globrix.tenure
Globrix property information: The tenure of the property e.g. 'leasehold'
FAQ About the Globrix meta tags.
Proposal
globrix.type
Globrix property information: Type of property e.g. 'semi-detatched house'
FAQ About the Globrix meta tags.
Proposal
globrix.underoffer
Globrix property information: Indicates if the property is under offer
FAQ About the Globrix meta tags.
Proposal
go-import
Defines a remote source code location and version control scheme for the Go programming language's toolchain. Content format:
import-prefix vcs repo-root
go tool documentation
Proposal
google
Multiple purposes:
Used to declare text that should not be translated by the Google Translate plugin ( will declare the whole page should not be translated, while is for text or paragraph areas you wish to not be translated.
Used "[t]o tell Google not to show a Sitelinks search box when your site appears in the search results" (implement with content="nositelinkssearchbox") (already in use).
Presumably, multiple meta elements named "google" should all be parsed but this is may not have been explicitly specified anywhere.
"notranslate":
Google blog post
"nositelinkssearchbox":
Google on Structured Data > Sitelinks Search Box
Nontranslation: Proposal
No Sitelinks search box: Proposed
google-play-app
Promoting Apps with Smart App Banners
[8]
Smart banners for Google Apps
Proposal
google-site-verification
Used to verify ownership for Webmaster Tools.
Google documentation
Proposal
gwt:property
Used to specify the locale client property
Locales in GWT
Proposal
handheldfriendly
Informs the BlackBerry browser that the content contained within the document is designed for small screens.
BlackBerry (handheldfriendly "largely obsolete")
Proposal
icas.datetime
A point or period of time associated with an event in the lifecycle of the resource represented in terms of an ICAS date and time format of unspecified information density (may include full, long, medium, short, or compressed forms).
a preliminary specification in the aaticas group on LinkedIn (
). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.
Proposal
icas.datetime.abbr
A point or period of time associated with an event in the lifecycle of the resource represented in terms of an ICAS abbreviated format such as "d2M03 t969".
a preliminary specification in the aaticas group on LinkedIn (
). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.
Proposal
icas.datetime.day
A point or period of time associated with an event in the lifecycle of the resource represented in terms of ICAS day-of-year format such as "2012 day 333 t969".
a preliminary specification in the aaticas group on LinkedIn (
). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.
Proposal
icas.datetime.long
A point or period of time associated with an event in the lifecycle of the resource represented in terms of ICAS long date format such as "UCN 12012 M03 Blue ❀ day 333 ❀ IDC zone(UT) t969 tt189". example
a preliminary specification in the aaticas group on LinkedIn (
). after a period of review, a specification for AAT ICAS meta keywords for HTML(5) will be referenced on an AAT ICAS area of the aatideas.org web site.
Proposal
icbm
Defines geographic position to which page is related to. The acronym stands for ICBM Intercontinental Ballistic Missile - an old, humorous allusion to the possible use of such coordinates.
Example:

Like geo.position except for value syntax.
GeoURL documentation
Proposal
IE_RM_OFF
If set to "true", disables Internet Explorer 11 Reading View button adjacent to address bar when the page is detected to have content suitable for Reading View. This is intended for pages that are not articles and are not intended to be read in IE 11 Reading View.
Microsoft: Reading View Guidelines and Information
In the Code tab, at the bottom where Opt Out is read.
Proposal
itemsPerPage
Used to identify the number of search results returned per page.
OpenSearch Specification
Proposal
keywords-not
Like keywords but instead keywords-not support Boolean NOT searches; useful for metaphors, satire/parody, and pages that say "this page is not about subject x" which therefore would be erroneously excluded by a NOT search against x.
BrittleBit.org spec
Proposal
license
Is used to to define the license under which a website is published.
Unofficial Documentation of license
Proposal
license:uri
Is used to to define the uri to the license, under which a website is published.
Unofficial Documentation of license:uri
Proposal
meta_date
The date used to indicate that the Metadata has been prepared and/or reviewed and approved by the Metadata Unit. Its purpose is administrative. (Used by "Autonomy".)
Health Canada Web Metadata Application Profile March 2009
Proposal
microtip
Specifies the cryptocurrency address (bitcoin, etc.) for sending tips to the people responsible for creating this page's content. This tag is used by various browser plugins that want to compensate the site's creators. Since it's microtipping instead of micropayments, there is no need to specify an amount.
Example:

Note: there can be multiple instances of this metatag on a page.
For full specification, see:
Proposal
mobile-agent
Specifies the mobile-compatible url of the web page. Used by mobile browsers and search engines to redirect mobile phone visitors to the proper mobile page.
The following properties can be used in the value of the content attribute:
url - The mobile-compatible url of the web page.
format - The format of the mobile page. An enum of "wml", "xhtml" and "html5".
Example:

Baidu Mobile SEO
Proposal
mobile-web-app-capable
Sets whether a web application can be added standalone to a home screen and launched in fullscreen mode. Also proposed as a vendor-neutral version of apple-mobile-web-app-capable.
Add to Homescreen - Google Chrome Mobile — Google Developers
(though a WHATWG or W3C spec would be preferred)
apple-mobile-web-app-capable (vendor specific synonym)
Proposal
mobileoptimized
Controls layout behavior in older versions of Internet Explorer (e.g., 6.5).
Microsoft Windows Mobile 6.5 documentation
Proposal
msapplication-config
"Pinned Sites" in Windows 8
The "msapplication-config" metadata defines the path to a browser configuration file, letting you set pinned sites customizations (such as tile background, badge updates and notifications) with this external XML file rather than metadata within the HTML markup of webpages.

Note
Without this metadata, IE11 looks for a default "browserconfig.xml" in the root directory of the server.
Browser configuration schema reference
Proposal
msapplication-navbutton-color
"Jump List" or "Pinned Sites" in Windows 7
The "msapplication-navbutton-color" metadata define the custom color of the Back and Forward buttons in the Pinned Site browser window. Any named color, or hex color value is valid.

Declaring Pinned Site Metadata
Proposal
msapplication-notification
"Pinned Sites" and "Live Tiles" in Windows 8.1
Used to make pinned sites on the start screen into live tiles. Usage:

Pinned site metadata reference
Proposal
msapplication-square150x150logo
msapplication-square150x150logo
Specifies the image to use as the wide tile, which is 310x150 pixels at 100% scaling.

Note
The
msapplication-square150x150logo
value is supported as of IE11 Preview and applies to tiles pinned to the Windows Start screen.
Pinned site metadata reference
Proposal
msapplication-square310x310logo
msapplication-square310x310logo
Specifies the image to use as the large tile, which is 310x310 pixels at 100% scaling.

Note
The
msapplication-square310x310logo
value is supported as of IE11 Preview and applies to tiles pinned to the Windows Start screen.
Pinned site metadata reference
Proposal
msapplication-square70x70logo
msapplication-square70x70logo
Specifies the image to use as the small tile, which is 70x70 pixels at 100% scaling.

Note
The
msapplication-square70x70logo
value is supported as of IE11 Preview and applies to tiles pinned to the Windows Start screen.
Pinned site metadata reference
Proposal
msapplication-starturl
"Jump List" or "Pinned Sites" in Windows 7
The "msapplication-starturl" metadata contains the root URL of the application. The start URL can be fully qualified, or relative to the current document. Only HTTP and HTTPS protocols are allowed. If this element is missing, the address of the current page is used instead.

Declaring Pinned Site Metadata
Proposal
msapplication-tap-highlight
Link highlighting in Internet Explorer
The "msapplication-tap-highlight" meta tag can be used to disable automatic highlighting of tapped links in Internet Explorer. Applies to IE10 on Windows Phone 8 and IE11 on Windows 8.1.

Link highlighting
Proposal
msapplication-task
"Jump List" or "Pinned Sites" in Windows 7
Jump List items act as entry points into the website even when the browser is not running. A Jump List can contain commonly used destinations and tasks. Some items apply to the whole site, and some apply only to specific users.
For example, to add a single task called "Check Order Status" specify a meta element in the head of your webpage, as follows:

Tasks in Jump List
Proposal
msapplication-TileColor
The "msapplication-TileColor" metadata define the background color of a tile in Pinned Sites in Windows 8. The tile color can be specified as a hex RGB color using CSS’s #rrggbb notation, via CSS color names, or by the CSS rgb() function.

High Quality Visuals for Pinned Sites in Windows 8
Proposal
msapplication-TileImage
The "msapplication-TileImage" metadata define the path to an image to be used as background for a tile in Pinned Sites in Windows 8. Tile images must be square PNGs 144px by 144px.

High Quality Visuals for Pinned Sites in Windows 8
Proposal
msapplication-tooltip
"Jump List" or "Pinned Sites" in Windows 7
The "msapplication-tooltip" metadata provides additional tooltip text that appears when you hover over the Pinned Site shortcut in the Windows Start menu or on the desktop.

Declaring Pinned Site Metadata
Proposal
msapplication-wide310x150logo
msapplication-wide310x150logo
Specifies the image to use as the medium tile, which is 150x150 pixels at 100% scaling.

Note
The
msapplication-wide310x150logo
value is supported as of IE11 Preview and applies to tiles pinned to the Windows Start screen.
Pinned site metadata reference
Proposal
msapplication-window
"Jump List" or "Pinned Sites" in Windows 7
The "msapplication-window" metadata sets the initial size of the Pinned Site window when it is launched for the first time. However, if the user adjusts the size of the window, the Pinned Site retains the new dimensions when it is launched again.
The following properties can be used in the value of the
content
attribute:
width - The window width in pixels. The minimum value is 800.
height - The window height in pixels. The minimum value is 600.

Declaring Pinned Site Metadata
Proposal
MSSmartTagsPreventParsing
Prevent a Microsoft browser from adding a certain kind of content to a page because users could be confused into thinking the added content was part of the original page. (It's likely only relatively few copies of the browser, a beta release never finalized, are still in the installed Win base, but the base is so large that even relatively few would still be a significant absolute quantity.)
This tag is used by Google:
Custom Search Help: Meta Tags
, as accessed 1-8-16. And "" appeared (with internal quote marks as singles) in the source code for <
[9]
>, as accessed 4-27-09.
BrittleBit.org spec
Proposal
msvalidate.01
One of the verification elements used by Bing.
Bing Webmaster Tools
Proposal
nonfiction
To reduce the "fake news" problem, this lets well-meaning page authors label satire and parody appropriately in metatags although unlabeled in content (not explicitly labeling being common in satire and parody). Characterize the principal content of the page as nonfiction, fiction, mixed, or other. This way, other websites and users needn't be fooled.
BrittleBit.org spec
fiction (antonym; see spec for usage)
Proposal
norton-safeweb-site-verification
Used to verify ownership of Website for Norton SafeWeb.
Norton SafeWeb Help Documentation
Proposal
origin
The
origin
meta tag is used to indicate the original source of a document.
The
origin
meta tag
Proposed
origin-trials
Used to enable experimental browser features for sites which are registered to participate in experimental trials.
Experimental Framework Trial Token Structure
Proposal
p:domain_verify
Used to register a site's domain with Pinterest as a "verified domain".
Example:

Pinterest Help Article
Proposal
page-version
When a page uploaded two or more times with the same last-modification date (per dc.modified, dcterms.modified, or article:modified_time metatag), distinguishing different uploads even on the same date can be done with the page-version metatag.
BrittleBit.org spec
Proposal
pingdom
Used by Pingdom monitoring services as a heartbeat verification. The heartbeat service will only consider the request successful if it contains the "pingdom" meta tag, with the content set according to a per-customer key.
Example:

Proposal
pinterest
Used to block pinterest from linking to content on the URL.
Example:

Pinterest Help Article
Proposal
prism:alternateTitle
An alternate title or alternate headline for a resource that may be used in a table of contents, a popup etc. and can vary with platform.
PRISM Basic Metadata Specification V3.0
Proposal
pro
Signify expertise as judged by an authority. Counterpart to pro-auth (which see). Useful to search engines and Web directories.
BrittleBit.org spec
Proposal
pro-auth
Signify an authority, subject to search engine's or directory's judgment of importance and credibility (the judgment could be by a human working for a search engine), so the authority's listing of experts can carry weight, making search results more useful.
Counterpart to pro (which see). Supported also by pro-auth-field (which see) and pro-auth-fragment (which see).
BrittleBit.org spec
Proposal
pro-auth-field
Signify an authority's claimed field of expertise, importance and validity to be judged by search engine or directory. Supports pro-auth (which see).
BrittleBit.org spec
Proposal
pro-auth-fragment
Signify which links from authority are links to experts, as distinct from other links. Supports pro-auth (which see).
BrittleBit.org spec
Proposal
rating
The Restricted to Adults label (RTA) provides a way for adult oriented websites to indicate that their content is off limits to children. RTA was introduced in 2006 and is currently used by a large number of adult web content providers. RTA is recognized by all major parental control filters.
Example:

RTA documentation
Proposal
referrer
Controls whether the user agent includes the Referer header in HTTP requests originating from this document
Referrer Policy
referer
Proposal
RepostUsAPIKey
Used to verify ownership of Website for Repost syndication service
Meta Headers used by Repost
Proposal
ResourceLoaderDynamicStyles
MediaWiki
's
ResourceLoader
uses this name with
content
set to the empty string. The purpose is to mark the DOM position before which dynamic styles should be added.
ResourceLoaderDynamicStyles
Proposal
review_date
The date a resource is scheduled for review by content creator in order to determine if it should be archived, updated or retained as is.
Health Canada Web Metadata Application Profile March 2009
IMS 6001-1-2, Metadata for Recordkeeping and Web Content
Proposal
revision
The revision of this page as reported by an underlying Version Control System. This is a free format string.
Meta Revision Specification
Proposal
revisit-after
revisit-after is used to tell search engines how often to recrawl the page. To our knowledge only one search engine has ever supported it, and that search engine was never widely used — at this point, it is nothing more than a good luck charm.
Google documentation
Proposal
rights
Assert legal rights for the page in a machine-parsable format. Rights could include those in copyright, for trade secrets, and in other intellectual property.
Talk
BrittleBit.org spec
Proposal
rights-standard
The purpose is to enable search engines and other cataloging services to compile the types of rights allocated to the work. (Does any search engine actually implement this?
hsivonen
07:34, 14 July 2011 (UTC))
This keyword does not provide, remove or alter any legal protections or designations.
Format:

element id - the HTML Element ID of the item these rights apply to
rights - what rights are assigned to the item
"pd" - Public domain
"cc by-sa" - Creative Commons Attribution
"cc by-nd" - Creative Commons NoDerivs
"cc by-nc" - Creative Commons Attribution-NonCommercial
"cc by-nc-sa" - Creative Commons Attribution-NonCommercial-ShareAlike
"cc by-nc-nd" - Creative Commons Attribution-NonCommercial-NoDerivs
Spec
Redundant with
Microdata vocabulary for licensing works
Proposal
robots
A comma-separated list of operators explaining how search engine crawlers should treat the content. This meta name is already supported by every popular search engine.
Possible values are "noarchive" to prevent cached versions, "noindex" to prevent indexing, and "nofollow" works as the link rel value with the same name.
The content value "NOODP" has been offered elsewhere, so I'm proposing it here. It blocks robots from using
Open Directory Project
descriptions of a website instead of Web pages' own meta descriptions. It may have been introduced by Microsoft.
The content value "NOYDIR" has been offered by Yahoo, so I'm proposing it here. It blocks Yahoo's robot from using the Yahoo directory's descriptions of a website instead of Web pages' own meta descriptions. Whether any other robot supports this is unknown but possibly no other search engine uses Yahoo's directory anyway.
About the Robots tag
; NOODP value:
Google
Yahoo
, NOYDIR value:
Yahoo
, as accessed 4-28-09
baiduspider (for targeting Baidu or Baiduspider only)
citeseerxbot (for targeting CiteSeerX only)
googlebot (for targeting Googlebot only)
googlebot-mobile (for targeting Googlebot-Mobile)
ia_archive (for targeting Internet Archive (Wayback Machine) or Alexa only)
msnbot (for targeting Microsoft or Bing only)
slurp (for targeting Yahoo or slurp only)
teoma (for targeting TEOMA or Ask.com only)
Proposal
rpuPlugin
Version of installed Repost syndication service plugin
Meta Headers used by Repost
Proposal
rqid
Request identifier of request that generated this page.
RequestID
Proposal
shareaholic:analytics
Enables or disables Shareaholic Analytics for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:article_author
A URL to the profile of the author of the content of the webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:article_author_name
Contains the name of the author of the content of the webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:article_modified_time
When the article was last modified for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:article_published_time
When the article was first published for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:article_visibility
Specifies whether a webpage should be publicly recommendable for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:drupal_version
Specifies Shareaholic for Drupal module version for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:image
An image URL which represents your webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:keywords
Keywords associated with the content of a webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:language
Language of the content of the webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:outstreamads
Enables or disables Shareaholic Outstream Ads for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:shareable_page
Specifies whether a webpage should be publicly shareable for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:site_id
Shareaholic Site ID for the website for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:site_name
The name which should be displayed for the overall site for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:title
Title associated with the content of a webpage for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:url
The canonical URL of your webpage that will be used as its permanent ID for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
shareaholic:wp_version
Specifies Shareaholic for WordPress plugin version for use with the Shareaholic Content Amplification system
Shareaholic CAS Specification
Proposal
signet:authors
Authors of a page for use with javascript signet library
Signet Revision Specification
Proposal
signet:links
links to related pages, for use with the javascript signet library
Signet Revision Specification
Proposal
skype_toolbar
Prevents the Skype browser extension from automatically seeking through the page and replacing telephone numbers (or any number the program's algorithm thinks is a telephone number) with its own custom presentation that allows direct invocation of the Skype program to call the telephone number.
Example:

Skype Info
Proposal
startIndex
Used to identify the index of the first search result in the current set of search results.
OpenSearch Specification
Proposal
startver
Used to verify WebApps for JokeNetwork's Start!-WebApp
JokeNetwork's Start Documentation
Proposal
subject-datetime
Identify the principal datetime ranges of the subject of the page’s content, such as the dates of an historical event.
BrittleBit.org spec
page-datetime
datetime-coverage
datetime-coverage-start
datetime-coverage-end
datetime-coverage-vague
Proposal
subject-system
Where another metatag provides a subject for the page, that subject should be selected in accordance with a standard system for classifying subjects, such as one used for academic or public libraries of books. This metatag identifies the system in use for the current page, using a standard controlled vocabulary of system identifiiers.
BrittleBit.org spec
subj-. . . or subj-* (namespace not approved thus synonym would be "subj-" plus whatever is after hyphen in token)
Proposal
supported-media
Indicates the range of media for which the page's viewing is supported. Not intended for use by browsers, but rather by referrers that make use of crawl data.
supported-media spec
Proposal
theme-color
Indicates a color associated with the web site's theme. Web browsers might use this color to theme their UI to be consistent with the web site's color scheme.
Usage:

Defined in HTML
Standard
thumbnail
The full URL of a file that provides a thumbnail for the HTML page.
(Note: This violates HTML5, section 4.2.5.2, which says this, because the value is a URL, must be a link element and not a meta element, but Google already recommends and parses this as a meta element.)
Google page
, as accessed Jan. 2, 2016. Original date unknown.
Proposed
topper
Notify website visitors of later changes; easier for website authors to maintain than RSS or Atom.
BrittleBit.org spec
Proposal
topper-major
Limit use of topper to major changes.
BrittleBit.org spec
Proposal
topper-minor
In use of topper, include minor changes.
BrittleBit.org spec
Proposal
totalResults
Used to identify the number of search results available for the current search.
OpenSearch Specification
Proposal
translator
The
translator
meta tag is used to give credit to, and provide contact info for, the translator of a document.
The
translator
meta tag
Proposed
twitter:app:country
If your application is not available in the US App Store, you must set this value to the two-letter country code for the App Store that contains your application.
Proposal
twitter:app:id:googleplay
String value, and should be the numeric representation of your app ID in Google Play.
Proposal
twitter:app:id:ipad
String value, should be the numeric representation of your app ID in the App Store.
Proposal
twitter:app:id:iphone
String value, should be the numeric representation of your app ID in the App Store.
Proposal
twitter:app:name:googleplay
Name of your Android app
Proposal
twitter:app:name:ipad
Name of your iPad optimized app
Proposal
twitter:app:name:iphone
Name of your iPhone app
Proposal
twitter:app:url:googleplay
Your app's custom URL scheme.
Proposal
twitter:app:url:ipad
Your app's custom URL scheme.
Proposal
twitter:app:url:iphone
Your app's custom URL scheme.
Proposal
twitter:card
The card type, which will be one of "summary", "photo", "app", or "player".
Proposal
twitter:creator
@username for the content creator / author.
Proposal
twitter:creator:id
Twitter ID for the content creator / author.
Proposal
twitter:data1
String value; value for labels such as price, items in stock, sizes, etc
Proposal
twitter:data2
String value; value for labels such as price, items in stock, sizes, etc
Proposal
twitter:description
A description of the content in a maximum of 200 characters.
Proposal
twitter:domain
Short URL assigned by Twitter to a website.
Proposal
twitter:image
A URL to the image representing the content.
Proposal
twitter:image0
A URL to the image representing the first photo in your gallery.
Proposal
twitter:image1
A URL to the image representing the second photo in your gallery.
Proposal
twitter:image2
A URL to the image representing the third photo in your gallery.
Proposal
twitter:image3
A URL to the image representing the fourth photo in your gallery.
Proposal
twitter:image:height
The height of the image representing the content.
Proposal
twitter:image:src
URL of image to use in the card. Image must be less than 1MB in size.
Proposal
twitter:image:width
The width of the image representing the content.
Proposal
twitter:label1
String value; label such as price, items in stock, sizes, etc
Proposal
twitter:label2
String value; label such as price, items in stock, sizes, etc
Proposal
twitter:player
HTTPS URL to iframe player. This must be a HTTPS URL which does not generate active mixed content warnings in a web browser
Proposal
twitter:player:height
Height of IFRAME specified in twitter:player in pixels
Proposal
twitter:player:stream
URL to raw stream that will be rendered in Twitter's mobile applications directly
Proposal
twitter:player:stream:content_type
The MIME type/subtype combination that describes the content contained in twitter:player:stream
Proposal
twitter:player:width
Width of IFRAME specified in twitter:player in pixels
Proposal
twitter:site
@username for the website used in the card footer.
Proposal
twitter:site:id
Twitter ID for the website used in the card footer.
Proposal
twitter:title
The title of the content as it should appear in the card.
Proposal
twitter:url
Canonical URL of the card content.
Proposal
typemetal.formatprefs
Per-file HTML formatting preferences used by the TypeMetal HTML editor
TypeMetal User Guide
Proposal
verify-v1
Superseded by google-site-verification. Legacy verification for Google Sitemaps.
Inside Google Sitemaps: More about meta tag verification
Proposal
version
The version of a web application according to the
Semantic Versioning
specification
Example:

Documentation
Proposal
vfb-version
Specifies a Visual Form Builder plugin version for Wordpress.
Visual Form Builder Documentation and specs
Proposal
viewport
Provides a way for documents to specify (using markup rather than CSS) the size, zoom factor, and orientation of the viewport that is used as the base for the document's
initial containing block
. The following properties can be used in the value of the
content
attribute:
width
height
initial-scale
minimum-scale
maximum-scale
user-scalable
Examples:


CSS Device Adaptation
Proposal
web_author
Credits the developer(s) responsible for the technical design of a website.
Documentation
designer
- for visual presentation
Proposal
witget
Used to verify ownership for Witget.com.
Example
Witget manual
Proposal
wot-verification
Used to verify ownership of WOT (Web Of Trust)
WOT's verify your site wiki page
Proposal
wt.ac
Advertising Click parameter
When a visitor to your site clicks on an ad, that action is referred to as an Ad Click. The following META tag tracks advertising clicks:

Defines the name of the advertisement clicked to reach a particular web page. The Ad Click must contain an external redirect back to the client. The redirect needs to include the necessary code to generate a hit to the SDC server. You can designate multiple Advertising Clicks using semicolons.
Examples:


The name of the advertisement clicked to reach a particular web page. To capture this information with DCS, the Advertising Click must contain an external redirect back to the client. The redirect needs to
include the necessary code to generate a hit to the DCS. The maximum length for each name is 64 bytes.
Webtrends Parameters
Proposal
wt.ad
Advertising View parameter
Visitors often view advertisements that they do not necessarily click on. You can use On-Site Advertising to determine the number of visitors to your web site who view particular ads. With this feature you can produce advertising reports for each of your clients.
If you are selling advertising space on your web site, for example, you can collect traffic statistics to help determine pricing schedules.
The following META tag tracks advertising views:

An Ad View occurs when a visitor views a page containing an ad. An ad is a link or graphic that contains an Ad Click parameter in the query portion of it's URL.
Webtrends Parameters
Proposal
wt.cg_n
Name of the Content Group
Used to configure the appropriate Webtrends advanced feature. These are just some of the more popular ones. These appear in your META tags. – showing you the web page, the source (meta tag), the log files entry and the subsequent WT report.
Example:

Webtrends Parameters
Proposal
wt.cg_s
Name of Content Sub-Group
Used to configure the appropriate Webtrends advanced feature. These are just some of the more popular ones. These appear in your META tags. – showing you the web page, the source (meta tag), the log files entry and the subsequent WT report.
Example:

Webtrends Parameters
Proposal
wt.mc_id
Identifies the ID of the marketing campaign
To attract new students, a university launches a marketing campaign by sending recruitment email to all graduating high school seniors in a metropolitan area. The email links to a special landing page in the university’s web site, containing the following META tag to track marketing campaigns.
Example:

You may use this parameter on the URL.
Example:

The Campaign ID 1X2GG34 represents recruits to be contacted by email
Webtrends Parameters
Proposal
WT.si_n
Scenario analysis parameter - scenario name
This defines a scenario name for the page or set of pages to be included in the scenario. This in turn produces a funnel type report in Webtrends.
Example:

Webtrends Parameters
Proposal
WT.si_p
Scenario analysis parameter - scenario step name
This defines a scenario step name for the page or set of pages to be included in the scenario. This in turn produces a funnel type report in Webtrends. It works when paired with metedata tag name WT.si_n.
Example:

Webtrends Parameters
Proposal
WT.si_x
Scenario analysis parameter - scenario step number
This defines a scenario step number for the page or set of pages to be included in the scenario. This in turn produces a funnel type report in Webtrends. It works when paired with metedata tag name WT.si_n, and as an alternative to Wt.si_p.
Example:

Webtrends Parameters
Proposal
wt.sv
Tracking Servers parameter
If your site is hosted on multiple servers, a server cluster, or a server farm, and you want to evaluate the performance of your load balancer, Webtrends can track page views for each server. To do so, populate the following META tag on all pages on each server:
Example:

Defines the name of the machine that serves the web page. If you have two servers (Server1 and Server2), you would make two copies of the META tag and designate CONTENT=“Server1” for deployment to pages on the first server and CONTENT=“Server2” for deployment to the same pages on the second server.
For a server farm, you can extract the value of the built-in server name and dynamically assign it to the
META tag using server-side scripting.
Example:


An Ad View occurs when a visitor views a page containing an ad. An ad is a link or graphic that contains an Ad Click parameter in the query portion of it's URL.
About WT.ad
Proposal
wt.ti
Tracking Page Titles
You may want to modify a page title before sending it to Webtrends in the following cases:
You are dealing with dynamic content pages identified by URL parameters, and the page title represents the title of the base URL page rather than the dynamic content page.
Unless you modify the page titles, all pages have the same title in the reports.
All pages have been assigned the same title, for reasons of style or company policy.
Even though URLs are displayed in addition to page title, the entire URL cannot be depended upon to distinguish one page from another.
Use server-side scripts to change the title to something that reflects the content of the pages so that you can identify them in reports. Next, pass the customized page titles to Webtrends, using the following META tag:

Defines the name of the title for this page.
Webtrends Parameters
Proposal
y_key
Used to verify ownership for Yahoo! Site Explorer
Yahoo! documentation
Proposal
yandex-verification
Used to verify ownership for Yandex Webmaster.
Yandex Webmaster ownership verification
Proposal
ZOOMCATEGORY
Category of page to be grouped in Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
ZOOMDESCRIPTION
Alternative page description for Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
ZOOMIMAGE
URL to image to be displayed alongside result in Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
ZOOMPAGEBOOST
Page boost factor to increase or decrease the relevance of page in Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
ZOOMTITLE
Alternative page title for Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
ZOOMWORDS
Additional keywords to be indexed for Wrensoft Zoom Search Engine.
Wrensoft Zoom Meta Documentation
Proposal
Proposals That Don't Meet the
Requirements
For a Registration
Note that these proposals can be moved back to the registry table if the problems listed in the rightmost column of this table are addressed.
Keyword
Brief description
Link to specification
Synonyms
Status
Registration requirement failure
blogcatalog
Used to verify ownership of Blog Catalog.com
Blog catalog site
Incomplete proposal
Claimed spec link is not a link to a spec
created
The datetime at which the document was created. The value is an ISO8601 date. The date MUST follow the
W3C Profile of ISO 8601
with a granularity of "Complete date:" or finer. The
BBC
use this name.
Incomplete proposal
Lacks link to a spec
expires
meta name='expires'
defines the expiration date of the page. This can be used for web pages in preparation for an upcoming event, e.g. a registration form for an exposition or competition, or other cases with a pre-set date when the document will no longer be valid, e.g. a product offer in a special sale or a support page for a product known not to be supported anymore from a given time onward.
Search engines should respond to this meta tag in a reasonable way, i.e. by removing the page from their main search results after the expiration date (possibly still returning the result in a special search for expired pages as long as the page exists and is not explicitly excluded via
robots.txt
or
meta name='robots'
etc.) or simply by indicating to the user that this result is out-of-date.
The content attribute should define the expiration date in accordance with
. The meta tag should not be used for pages without expiration date. However, for historical reasons, search engines should also interpret other date formats where possible and should be prepared to find values such as "", "0", "no" and "never". Such non-date values are to be interpreted as no expiration date.
Correctly formatted example:

This tag is not to be confused with and has a different meaning than
meta http-equiv='expires'.
Incomplete proposal
Lacks link to a spec
fb:admins
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
fb:page_id
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
gm-gpx-v
Wordpress Plugin Google Maps GPX Viewer
Google Maps GPX Viewer
Incomplete proposal
Claimed spec link is not a link to a spec
google-translate-customization
Used to verify ownership for Website Translator.
Incomplete proposal
Lacks link to a spec
nextgen
Used for nextgen gallery plugin in wordpress
Alexa FAQ About this meta attribute Reference
Incomplete proposal
Unrelated spec link
nibbler-site-verification
Used to verify ownership of Nibbler site
Nibbler site
Incomplete proposal
Claimed spec link does not link to a spec
og:description
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
og:image
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
og:site_name
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
og:title
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
og:type
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
og:url
Open Graph Protocol by Facebook developers
Facebook developers
Incomplete proposal
The spec specifies this to be a value of the property attribute--not a meta keyword
property="og:*"
Metadata used by the Open Graph protocol (used by Facebook). Note: currently these are defined as:
FAQ About the Open Graph protocol from Facebook.
Doesn't belong in this registry
Not a value to be used in the
name
attribute
resolutions
Authoring web sites to use resolution independent images that display beautifully on high-resolution displays should be made as easy as possible for developers and should not require JavaScript to accomplish.
To accomplish this, I propose a new HTML Meta Tag,
resolutions
, that can be used to specify that high-resolution versions of images linked to from the page are available and that the browser should use them in place of the lower-resolution default images if it detects that a user is using a high-resolution screen. The resolutions meta tag lists the device-pixel ratios supported by images in the page.
So, for example…

… means that the developer is telling the browser that she has created 2x resolution images for the images linked to from the current page and named them with a @2x suffix.
To illustrate, if her image tag is as follows…

… then she has two image files under /images: the low-resolution default (flower.jpg), and a higher-resolution (200%) version named
[email protected]
(This is the same naming convention already used by Apple in its Cocoa Touch framework for automatically loading in higher-resolution versions of images.)
Based on the meta tag, if the browser detects that the user is running at a
min-device-pixel-ratio
of 2.0, it will automatically ask for the 2x version of the image (
[email protected]
) instead of the default image as specified in the image tag.
Finally, so as not to flood external sites with high-resolution image requests, this functionality would only work for local images specified via relative links.
Multiple resolutions
The resolutions tag can also contain a list of supported device-pixel ratios so as to support even higher-resolution displays when and if they become available in the future.
For example:

In this case, the developer would provide 2x, 4x, and 8x versions of all images. So, in the running example, she would make flower.jpg,
[email protected]
[email protected]
, and
[email protected]
Advantages
The advantages of this approach are several:
Makes it very simple for developers to support high-resolution displays like the iPhone 4's Retina screen
Does not require JavaScript
Does not change the default way that things work (if the meta tag is not specified, the browser simply behaves as it always has).
Proposal for native browser support of high-resolution image substitution
How to make your web content look stunning on the iPhone 4’s new Retina display
Incomplete proposal
Lacks link to a spec
Failed Proposals
Keyword
Brief description
Link to more details
Synonyms
Status
bot-. . .
Old MetaExtensions revision diff
edit
Unendorsed
cache
This doesn't actually work; use HTTP headers instead.
Value must be "public", "private", or "no-cache". Intended as a simple way to tell user agents whether to store a copy of the document or not. An alternate for HTTP/1.1's cache-control; for publishers without access to modifying cache-control.
none
Unendorsed
DC.
Dublin Core, maintained by Dublin Core MetaData Initiative (DCMI), is an extensive system with some overlap with non-DC names.
This reserves all strings that begin with DC and a dot.
Not true; DC-HTML doesn't use hardwired prefixes, but defines the prefixes using link/@rel="scheme.prefix"
DCMI
Unendorsed
dir-content-pointer
No longer useful. The function is better performed with HTML markup.
Old MetaExtensions revision diff
edit
Unendorsed
no-email-collection
HTML5 prohibits URL-valued meta names. They should be rel keywords instead.
Intended to reference legal policy of web site indicating that harvesting of e-mail addresses on the site is not permitted and in violation of applicable laws such as the CAN-SPAM Act of 2003.
Project Honey Pot
Unendorsed
Retrieved from "
Category
Registries
Navigation menu