document.write('
解析:
<! DOCTYPE html>
<html>
<head>
<Title>Page title</title>
</head>
<body>
<header>
<h1>Page title</h1>
</header>
<nav>
<!--Navigation-->
</nav>
<section id="intro">
<!--Introduction-->
</section>
<section>
<!--Main content area-->
</section>
<aside>
<!--Sidebar-->
</aside>
<footer>
<!--Footer-->
</footer>
</body>
</html>
');