css

/* Keyword values */
overflow-block: visible;
overflow-block: hidden;
overflow-block: clip;
overflow-block: scroll;
overflow-block: auto;

/* Global values */
overflow-block: inherit;
overflow-block: initial;
overflow-block: revert;
overflow-block: revert-layer;
overflow-block: unset;

The overflow-block property is specified as a single <overflow> keyword value:

overflow-block = 
visible |
hidden |
clip |
scroll |
auto

html

<ul>
  <li>
    <code>overflow-block: hidden</code> (hides the text outside the box)
    <div id="hidden">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur.
    </div>
  </li>

  <li>
    <code>overflow-block: scroll</code> (always adds a scrollbar)
    <div id="scroll">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur.
    </div>
  </li>

  <li>
    <code>overflow-block: clip</code> (hides the text outside the box beyond the
    overflow clip edge)
    <div id="clip">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur.
    </div>
  </li>

  <li>
    <code>overflow-block: visible</code> (displays the text outside the box if
    needed)
    <div id="visible">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur.
    </div>
  </li>

  <li>
    <code>overflow-block: auto</code> (on most browsers, equivalent to
    <code>scroll</code>)
    <div id="auto">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim
      veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
      commodo consequat. Duis aute irure dolor in reprehenderit in voluptate
      velit esse cillum dolore eu fugiat nulla pariatur.
    </div>
  </li>
</ul>

css

div {
  border: 1px solid black;
  width: 250px;
  height: 100px;
  margin-bottom: 120px;
}

#hidden {
  overflow-block: hidden;
}
#scroll {
  overflow-block: scroll;
}
#clip {
  overflow-block: clip;
}
#visible {
  overflow-block: visible;
}
#auto {
  overflow-block: auto;
}