var intervalId = null; 
		function slideAd(id,nStayTime,sState,nMaxHth,nMinHth){ 
		  this.stayTime=nStayTime*500 || 80000;  /*出现时间和停留时间*/
		  this.maxHeigth=nMaxHth || 200; 
		  this.minHeigth=nMinHth || 1; 
		  this.state=sState || "down" ; 
		  var obj = document.getElementById(id); 
		  if(intervalId != null)window.clearInterval(intervalId); 
		  function openBox(){ 
		   var h = obj.offsetHeight; 
		   obj.style.height = ((this.state == "down") ? (h + 2) : (h - 2))+"px"; 
			if(obj.offsetHeight>this.maxHeigth){ 
			window.clearInterval(intervalId); 
			intervalId=window.setInterval(closeBox,this.stayTime); 
			} 
			if (obj.offsetHeight<this.minHeigth){ 
			window.clearInterval(intervalId); 
			obj.style.display="none"; 
			} 
		  } 
		  function closeBox(){ 
		   slideAd(id,this.stayTime,"up",nMaxHth,nMinHth); 
		  } 
		  intervalId = window.setInterval(openBox,1); 
		}