<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <title>Opacity on Document</title>
  <style type="text/css" media="screen">
    html {
      background-color: blue;
    }
    body {
      margin: 50px;
      background-color: gray;
    }
  </style>
</head>
<body>
<p>The document background should be red, and the body gray. The rest of the viewport should be white. The document and body should have opacity of 0.3.</p>
<script type="text/javascript" charset="utf-8">
  // Do this dynamically to avoid pixels from the previous test in potentially unpainted areas
  document.documentElement.style.backgroundColor = 'green';
  document.documentElement.style.opacity = 0.3;
</script>
</body>
</html>