css/css-pseudo/highlight-z-index-001.html

<!DOCTYPE html>

  <meta charset="UTF-8">

  <title>CSS Pseudo-Elements Test: highlight pseudo-element drawn below positioned element</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-painting">
  <link rel="match" href="highlight-z-index-001-ref.html">

  <meta name="assert" content="This test checks that the ::selection pseudo-element must be drawn below a relatively positioned element. In this test, such relatively positioned element is a preceding sibling element.">

  <style>
  div
    {
      font-size: 48px;
      line-height: 1.25; /* computes to 60px */
    }

  div#rel-positioned-sibling
    {
      background-color: yellow;
      color: green;
      display: inline-block;
      position: relative;
      top: 1.25em;
    }

  div#test::selection
    {
      background-color: red;
      color: yellow;
    }
  </style>

  <script>
  function startTest()
  {
  var targetRange = document.createRange();
  /* We first create an empty range */
  targetRange.selectNodeContents(document.getElementById("test"));
  /* Then we set the range boundaries to the children of div#test */
  window.getSelection().addRange(targetRange);
  /* Finally, we now select such range of content */
  }
  </script>

  <body onload="startTest();">

  <p>Test passes if "Text sample" is green and if its background color is yellow.

  <div id="rel-positioned-sibling">Test sample</div>

  <div id="test">Test sample</div>