웹 페이지 양측 부상 광고 js 코드

<script type="text/javascript">
var delta=0.08
	var collection;
	function floaters() {
		this.items	= [];
		this.addItem	= function(id,x,y,content)
				  {
					document.write('<DIV id='+id+' style="z-index: 1000; POSITION: absolute;  width:80px; height:60px;left:'+(typeof(x)=='string'?eval(x):x)+'px;top:'+(typeof(y)=='string'?eval(y):y)+'px">'+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 + 'px';
					}

				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 + 'px';
					}
				followObj.style.display	= '';
			}
		}	
		
	var theFloaters		= new floaters();
	// 
	theFloaters.addItem('followDiv1','document.body.clientWidth-106',138,'<img border="0" src="http://img.amp.ad.sina.com.cn/sax/screenimage/998022e0a53c4516b733880687539b91.jpg" style="width:120px;height:270px;border:0" alt="http://img.amp.ad.sina.com.cn/sax/screenimage/998022e0a53c4516b733880687539b91.jpg">');
	// 
	theFloaters.addItem('followDiv2',6,138,'<img border="0" src="http://img.amp.ad.sina.com.cn/sax/screenimage/998022e0a53c4516b733880687539b91.jpg" style="width:120px;height:270px;border:0" alt="http://img.amp.ad.sina.com.cn/sax/screenimage/998022e0a53c4516b733880687539b91.jpg">');
	theFloaters.play();
</script>