页头下拉广告，加了关闭按钮，不闪屏

把图片地址换成你自己的图片就可以了

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>像163网站顶部展出的大幅广告</title>
   <script type="text/javascript" language="javascript">
    var time = 500;
    var h = 0;
    function addCount()
    {
        if(time>0)
        {
            time--;
            h = h+5;
        }
        else
        {
            return;
        }
        if(h>=500) //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()",8000); //停留时间自己适当调整
    }
    </script>

    <script type="text/javascript" language="javascript">
    var T = 500;
    var N = 500; //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);
    }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div id="ads" style="margin:auto; display:none; 100%; top:0px; height:0px; border:solid 1px #000; background-color:#fafafa; position:relative; overflow:hidden; text-align:center;">
        <img src="C:\Documents and Settings\Administrator\My Documents\My Pictures\51.bmp" width="100%" alt="" /><div id="close" style="position:absolute; right:50px; bottom:20px; cursor:hand;" >
<img src='close.gif' onClick='javascript:document.getElementById("ads").style.display = "none";document.getElementById("close").style.display = "none"' width='100' height='14' border='0' vspace='3' alt='关闭广告'></div>
    </div>

    <div style="margin:auto; 100%; height:200px; border:solid 1px #000; background-color:#fafafa; text-align:center;">
        网站主体内容
    </div>
<table><tr><td style="position:relative">

</td></tr></table>
    </form>
</body>
</html>