JS 广告飘浮

<script language="javascript" type="text/javascript">
            // JavaScript Document
            //设置广告块 
            var divLeft = 0;
            //设置广告块初始左边位置 
            var divTop = 0;
            //设置广告块初始顶部位置 
            var divWidth = 80;
            //设置广告块宽度 
            var divHeight = 80;
            //设置广告块高度 
            var divImg = "<%=imgUrl%>";
            //设置广告图片的URL地址 
            var divUrl = "<%=aid%>";
            //设置广告链接 
            var divTitle = "<%=talented%>";
            //设置div标题
            document.write("<DIV id=\"adDiv\" style=\"position:absolute; left:"+divLeft);
            document.write("px; top:"+divTop+"px; width:"+divWidth+"px; height:"+divHeight);
            document.write("px; z-index:1;\" onMouseOver=\"javascript:window.clearInterval(varId)\"");
            document.write(" onMouseOut=\"javascript:beginMoveAd();\"><a href=\""+divUrl+"\" target=\"_blank\">");
            document.write("<img src=\""+divImg+"\" border=\"0\" alt=\""+divTitle+"\"></a><br>");
            document.write("<a href=\"javascript:\" onclick=\"document.getElementById('adDiv').style.display='none';\">");
            document.write("<font color=\"#FFFFFF\">关闭广告</font></a>");
            document.write("</DIV>");
            //飘浮广告 
            var _stepx=2;_stepy=2;
            //初始化每次偏离的象素 
            var moveSpeed=40;
            //速度 
            var varId;
            //获取setInterval的ID 
            function moveAd()
            {
             //飘浮广告主函数
             var adLeft=parseInt(adDiv.style.left);
             var adTop=parseInt(adDiv.style.top);
             var adWidth=parseInt(adDiv.style.width);
             var adHeight=parseInt(adDiv.style.height);
             var _bodyLeft=document.body.scrollLeft;
             var _bodyTop=document.body.scrollTop;
             var _bodyHeight=document.body.clientHeight+_bodyTop;
             var _bodyWidth=document.body.clientWidth+_bodyLeft;
             if(adLeft<=_bodyLeft)
             {
              _stepx=2;
             }
             if(adTop<=_bodyTop)
             {
              _stepy=2;
             } 
             if((adLeft+adWidth)>=_bodyWidth)
             {
              _stepx=-2;
             }
             if((adTop+adHeight)>=_bodyHeight)
             {
              _stepy=-2;
             }
             adDiv.style.left=adLeft+_stepx;
             adDiv.style.top=adTop+_stepy;
            }            function beginMoveAd()            {
             //启动飘浮
             varId = window.setInterval("moveAd()",moveSpeed);
            }
             //给窗体的load事件附加飘浮函数
            window.onload=beginMoveAd;
    </script>只要把以下这行代码加上飘浮函数就出现问题
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
经检查是JS没符合W3C标准
如果在JS飘浮广告符合W3C标准呢