JS + CSS + DIV 实现动画式折叠菜单

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
 <HEAD>
  <TITLE> New Document </TITLE>
  <style type="text/css">
 #data1{position:absolute;top:100px;left:100px;padding:0;width:200px;height:200px;
 background-color:#ff0;clip:rect(0px,200px,200px,0px);}
 #data1 h3{margin:0;padding:5px;font-size:smaller;background-color:#006;color:#fff;}
 #contained{margin:10px;}
  </style>
<SCRIPT LANGUAGE="JavaScript">
<!--
 var bottom = 200;
 var hidden = false;
 var obj = null;
 function clipItem(){
  obj = document.getElementById("data1");
  if(hidden){
   showItem();
  }else{
   hideItem();
  }
 }

 function hideItem(){
  bottom -=20;
  var clip = "r