var intervalId = null;
var nTag=0;
function slideAd(id,nStayTime,sState,nMaxHth,nMinHth){
        this.stayTime=nStayTime*1000 || 3000;
        this.maxHeigth=nMaxHth || 150; //广告最大高度
        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 +5 ) : (h - 5))+"px";
                
                if(obj.offsetHeight>=this.maxHeigth){
                　        window.clearInterval(intervalId);
                　        intervalId=window.setInterval(closeBox,3000);
                }
                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,4);
}

function chk(topXLHeight){
        (this.document.readyState=="complete")?slideAd('slideAD',1000,'down',topXLHeight,1):setTimeout('chk('+topXLHeight+')',1000);   
}