JS+CSS随屏幕滚动浮动层

<!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>

<title>JS+CSS随屏幕滚动浮动层</title>
<style>
html,body{
  height:2000px;
}
</style>
</head>
<body>
<div id="aa" style="200px;height:200px;background:#c0c0c0;" >
<div align="right"><a href="javascript:viod(0)" onclick="divclose()">关闭</a></div>

</div>

</body>
</html>
<script>
    function scroll(p){
     var d = document,w = window,o = d.getElementById(p.id),ie6 = /msie 6/i.test(navigator.userAgent);
     if(o){
      o.style.cssText +=";position:"+(p.f&&!ie6?'fixed':'absolute')+";"+(p.r?'left':"right")+":0;"+(p.t!=undefined?'top:'+p.t+'px':'bottom:0');
      if(!p.f||ie6){
       -function(){
           var t = 500,st = d.documentElement.scrollTop||d.body.scrollTop,c;
                 c = st  - o.offsetTop + (p.t!=undefined?p.t:(w.innerHeight||d.documentElement.clientHeight)-o.offsetHeight);
              c!=0&&(o.style.top = o.offsetTop + Math.ceil(Math.abs(c)/10)*(c<0?-1:1) + 'px',t=10);
              setTimeout(arguments.callee,t)
          }()
      }
     }
    }
    scroll({
     id:'aa'

    })
    function divclose()
    {
        document.getElementById("aa").style.display='none';
    }
</script>