Demo

<!doctype html>
<html>
<head>
<title>HTML Test</title>
<script type="text/javascript">
// Say hello world until the user starts questioning
// the meaningfulness of their existence.
function helloWorld(world) {
  for (var i = 42; --i >= 0;) {
    alert('Hello ' + String(world));
  }
}
</script>
<style type="text/css">
p { color: pink }
b { color: blue }
u { color: "umber" }
</style>
</head>
<body>
<h1>Hello world!</h1>
</body>
</html>