对联广告不能滚动问题
各位：
　　　新加了可以上下滚动的对联广告在首页，但是被绑住了似的不能上下岁页面滚动了，很奇怪，只要把页面的 <DOCTYPE……> 声明去掉就可以，请问为什么？
　　　　另外，为了保持页面的标准性，不想去掉这个声明，有什么办法？


<div   id= "center ">
<!--这里是中间主体块-->
</div>
<!--以下是ｊｓ代码-->
<scr...>
var   showad   =   true;
var   Toppx   =   100;       //上端位置
var   AdDivW   =   100;     //宽度
var   AdDivH   =   300;     //高度
var   PageWidth   =   800;   //页面多少宽度象素下正好不出现左右滚动条
var   MinScreenW   =   1024;   //显示广告的最小屏幕宽度象素  
var   ClosebuttonHtml   =   ' <div   align= "right "   style= "position:   absolute;top:280px;right:0px;margin:2px;padding:2px;z-index:2000; "> <a   href= "javascript:; "   onclick= "hidead() "   style= "color:#666666;text-decoration:none;font-size:12px; "> 关闭 </a> </div> '
var   AdContentHtml   =   ' <div   align= "center "   style= "color:green;font-size:23pt;font-family:黑体; "> <img   src/images/dlgg.gif "   width= "100 "   height= "300 "> </div> ';
document.write   ( ' <div   id= "javascript.LeftDiv "   style= "position:   absolute;border:   0px   solid   #336699;background-color:#EEEEE2;z-index:1000;width: '+AdDivW+ 'px;height: '+AdDivH+ 'px;top:-1000px;word-break:break-all;display:none; "> '+ClosebuttonHtml+ ' <div> '+AdContentHtml+ ' </div> </div> ');
document.write   ( ' <div   id= "javascript.RightDiv "   style= "position:   absolute;border:   0px   solid   #336699;background-color:#EEEEE2;z-index:1000;width: '+AdDivW+ 'px;height: '+AdDivH+ 'px;top:-1000px;word-break:break-all;display:none; "> '+ClosebuttonHtml+ ' <div> '+AdContentHtml+ ' </div> </div> ');
function   scall(){
  if(!showad){return;}
  if   (window.screen.width <MinScreenW){
    alert( "临时提示：\n\n显示器分辨率宽度小于 "+MinScreenW+ ",不显示广告 ");
    showad   =   false;
    document.getElementById( "javascript.LeftDiv ").style.display= "none ";
    document.getElementById( "javascript.RightDiv ").style.display= "none ";
    return;
  }
  var   Borderpx   =   ((window.screen.width-PageWidth)/2-AdDivW)/2;
  document.getElementById( "javascript.LeftDiv ").style.display= " ";
  document.getElementById( "javascript.LeftDiv ").style.top=document.body.scrollTop+Toppx;
  document.getElementById( "javascript.LeftDiv ").style.left=document.body.scrollLeft+Borderpx;
  document.getElementById( "javascript.RightDiv ").style.display= " ";
  document.getElementById( "javascript.RightDiv ").style.top=document.body.scrollTop+Toppx;
  document.getElementById( "javascript.RightDiv ").style.left=document.body.scrollLeft+document.body.clientWidth-document.getElementById( "javascript.RightDiv ").offsetWidth-Borderpx;
}
function   hidead()
{
  showad   =   false;
  document.getElementById( "javascript.LeftDiv ").style.display= "none ";
  document.getE