​x
 
<!DOCTYPE html>
<html>
<body id="myid" class="mystyle">
​
<script>
var x=document.getElementsByTagName('body')[0];
document.write("Body CSS 类：" + x.className);
document.write("<br>");
document.write("另一个替代方法：");
document.write(document.getElementById('myid').className);
</script>
​
</body>
</html>
​