var time = 500;
var h = 0;
function addCount()
{
	if(time>0)
	{
    	time--;
        h = h+5;
    }
    else
    {
    	return;
    }
    if(h>400)  //高度
    {
    	return;
    }
    document.getElementById("ads").style.display = "";
    document.getElementById("ads").style.height = h+"px";
    setTimeout("addCount()",30); 
}
window.onload = function showAds()
{
	addCount();
    setTimeout("noneAds()",15000); //停留时间自己适当调整
}

var T = 260;
var N = 400; //高度
function noneAds()
{
	if(T>0)
    {
    	T--;
    	N = N-5;
     }
     else
     {
    	return;
     }
     if(N<0)
     {
     	document.getElementById("ads").style.display = "none";
        return;
     }
        
     document.getElementById("ads").style.height = N+"px";
     setTimeout("noneAds()",30);
}