css/css-contain/contain-size-select-elem-005.html

<!DOCTYPE HTML>
<html>
<head>
  <meta charset="utf-8">
  <title>CSS Test: 'contain: size' on select objects should cause them to be sized as if they have no contents.</title>
  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
  <link rel="help" href="https://drafts.csswg.org/css-contain/#containment-size">
  <link rel="match" href="contain-size-select-elem-005-ref.html">
  <style>
  select {
    contain: size;
    color: transparent;
    /* We make scrollbars transparent because some <option> elements can cause
       overflow, which can cause scrollbars to be active in the test and
       inactive in the reference.  But the test only cares about the sizing. */
    scrollbar-color: transparent transparent;
  }
  .fsMedium {
    /* custom styling for some select elements, which is allowed to influence
       their size (in the same way that it influences the size of an empty
       select element): */
    font-size: 10px;
  }
  .fsSmall {
    /* custom styling for some option elements (which would make their parent
       select elem shorter, except for the fact that it's size-contained): */
    font-size: 6px;
  }
  </style>
</head>
<body>
  <!-- No contents: -->
  <select multiple                 ></select>
  <select multiple size="1"        ></select>
  <select multiple class="fsMedium"></select>

  <!-- Empty option: -->
  <select multiple                 ><option></option></select>
  <select multiple size="1"        ><option></option></select>
  <select multiple class="fsMedium"><option></option></select>

  <br><br>

  <!-- Nonempty option: -->
  <select multiple                 ><option>X</option></select>
  <select multiple size="1"        ><option>X</option></select>
  <select multiple class="fsMedium"><option>X</option></select>

  <!-- Nonempty option with custom font-size: -->
  <select multiple                 ><option class="fsSmall">X</option></select>
  <select multiple size="1"        ><option class="fsSmall">X</option></select>
  <select multiple class="fsMedium"><option class="fsSmall">X</option></select>
</body>
</html>