广告悬浮框

此代码可以实现，但不是很好，IE浏览器下是显示在右边（正确），火狐和谷歌浏览器显示在左边，定位失效。 还有无法随浏览器下拉而移动。

<script type="text/javascript">

var delta=0.5;
var collection;
var closeB=false;
function floaters() {
   this.items = [];
   this.addItem = function(id,x,y,content)
   {
      document.write('<DIV id='+id+' style="Z-INDEX: 10; POSITION: absolute;   width:80px; height:60px;left:'+(typeof(x)=='string'?eval(x):x)+';top:'+(typeof(y)=='string'?eval(y):y)+'">'+content+'</DIV>');
     
      var newItem     = {};
      newItem.object    = document.getElementById(id);
      newItem.x     = x;
      newItem.y     = y;
      this.items[this.items.length]   = newItem;
   }
   this.play = function()
   {
      collection     = this.items
      setInterval('play()',30);
    }
   }
   function play()
   {
    if(screen.width<=800 || closeB)
    {
     for(var i=0;i<collection.length;i++)
     {
      collection[i].object.style.display = 'none';
     }
     return;
    }
    for(var i=0;i<collection.length;i++)
    {
     var followObj   = collection[i].object;
     var followObj_x   = (typeof(collection[i].x)=='string'?eval(collection[i].x):collection[i].x);
     var followObj_y   = (typeof(collection[i].y)=='string'?eval(collection[i].y):collection[i].y);     if(followObj.offsetLeft!=(document.body.scrollLeft+followObj_x)) {
      var dx=(document.body.scrollLeft+followObj_x-followObj.offsetLeft)*delta;
      dx=(dx>0?1:-1)*Math.ceil(Math.abs(dx));
      followObj.style.left=followObj.offsetLeft+dx;
      }     if(followObj.offsetTop!=(document.body.scrollTop+followObj_y)) {
      var dy=(document.body.scrollTop+followObj_y-followObj.offsetTop)*delta;
      dy=(dy>0?1:-1)*Math.ceil(Math.abs(dy));
      followObj.style.top=followObj.offsetTop+dy;
      }
     followObj.style.display = '';
    }
   }
   function closeBanner()
   {
    closeB=true;
    return;
   } 
   var theFloaters   = new floaters();
//

theFloaters.addItem('followDiv1','document.body.clientWidth-115',0,'<a onClick="closeBanner();" href=http://www.invipshop.com/ target=_blank><img src=images/Ad_1.jpg width=112 height=224 border=0></a><br><img src=images/close.gif onClick="closeBanner();">');
theFloaters.play(); 
</script>

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