<html>
<body id="myid" class="mystyle">
<script>
var x=document.getElementsByTagName('body')[0];
document.write("Body 元素 CSS 类为: " + x.className);
document.write("<br>");
document.write("另一种方式: ");
document.write(document.getElementById('myid').className);
</script>
</body>
</html>