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 ="width: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 >