<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
  <head>
    <title>This is a title</title>
    <style>
    /* comment */
    #xyz { color: red; }
    h1 { font: "Comic Sans"; }
    </style>
  </head>
  <body>
    <p id="xzy">Hello world!</p>
  </body>
  <script>
    document.body.appendChild(document.createTextNode('Hello World!')); // comment
  </script>
</html>