<!DOCTYPE html>
<html>
<head>
  <title>CSS 2.1 Test Suite: :first-letter</title>
  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu" />
  <link rel="author" title="Mozilla Corporation" href="http://mozilla.com/" />
  <link rel="help" href="http://www.w3.org/TR/CSS21/selector.html#first-letter"/>
  <meta name="flags" content="dom" />
  <style>
  div { color: black; }
  div::first-letter { color: green; }
  </style>
</head>
<body>
  <div>
    <span>
      
    </span>
  </div>
  <script>
    document.body.offsetWidth;
    document.getElementsByTagName("span")[0].firstChild.data = "This is text";
  </script>
</body>
</html>