<!DOCTYPE html>
<html>
<head>
<script>alert(/123/);</script>
</head>
<body>
<h3>1. only</h3><h2>2. one</h2><h1>3. alert</h1><script>alert(document.domain);</script>
</body>
</html><!DOCTYPE html>
<html>
<head>
<script>alert(/123/);</script>
</head>
<body>
<h3>1. only</h3><h2>2. one</h2><h1>3. alert</h1><script>alert(document.domain);</script>
</body>
</html>