    <!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>