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<html>
<head>
<meta charset="utf-8">
<title>W3Cschool(w3cschool.cn)</title>
<base id="htmldom" href="http://www.w3cschool.cn/jsref/">
</head>
<body>
<p>基础URL是:
<script>
document.write(document.getElementById("htmldom").href);
</script>
</p>
</body>
</html>