JavaScript实现简单的Tab样式切换功能

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<script language="javascript" type="text/javascript">
var lastObj=null;
var lastIdx=1;
function test(obj,idx){
 if(!lastObj){
 lastObj = document.getElementById("test");
 lastIdx = 1;
 }
 lastObj.className = "new"+lastIdx;
 var old = document.getElementById("list"+lastIdx);
 if(old)old.style.display="none";
 obj.className = "class"+idx;
 var n = document.getElementById("list"+idx);
 if(n)n.style.display="block";
 lastObj = obj;
 lastIdx = idx;
}
</script>
<style type="text/css">
 .class1{ color:#FF0000}
 .new1{ color:#996633}
 .class2{ color:#FF0000}
 .new2{ color:#996633}
</style>
<title>JS实现样式切换</title>
</head>
<body>
<a href="#" class="class1" id="test" onclick="test(this,1)">list1</a>
<a href="#" class="new2" onclick="test(this,2)">list2</a>
<div id="list1">
test1
</div>
<div id="list2" style="display:none">
test2
</div>
</body>
</html>