以下是代码，我想让红色部分的2个图片不随滚动条拉动而浮动（就是要让这2个图片位置是固定的），红色部分代码该怎么改？帮小弟一下，偶不怎么懂JS，谢谢！
var delta=0.20
    var collection;
    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()',10);
                 }
        }
        function play()
        {

            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 closeAd1(){
followDiv1.style.visibility='hidden';}
function closeAd2(){
followDiv2.style.visibility='hidden';}
    var theFloaters        = new floaters();
theFloaters.addItem('followDiv1',2,500,'<a href=# target=_blank><img src=images/guanggao/adyou.gif border=0></a>');
    theFloaters.addItem('followDiv2',2,5,'<a href=# target=_blank><img src=images/guanggao/adyou.gif border=0></a>');
    theFloaters.addItem('followDiv3',894,5,'<a href=# target=_blank><img src=images/guanggao/adyou.gif border=0></a>');    theFloaters.play();