怎么实现图片的滚动

<div id="ess_ctr1501_ModuleContent"><span class="Normal" id="ess_ctr1501_HtmlModule_HtmlHolder">
  <DIV id="demo" style="OVERFLOW: hidden; WIDTH: 770px; HEIGHT: 120px" align="center">
   <TABLE cellSpacing="0" cellPadding="0" width="100%" align="center" border="0" cellspace="0">
    <TBODY>
     <TR>
      <TD id="demo1" width="100%" height="120">
       <!--图片列表开始-->
       
         <TABLE cellPadding="0" width="100%" align="center" border="0" cellspace="0" cellspacing="0">
          <TR>
        
         <td align="center" valign="top">
          <a href='' target="_blank" title=''>
          <img src='UploadPhoto/xz11.bmp' height="100" width="130" border="0"></a>
                  </td>
         
        
         <td align="center" valign="top">
         <a href='' target="_blank" title=''>
         <img src='UploadPhoto/DSC_2668-2.jpg' height="100" width="130" border="0"></a>
         </td>
         
         <td align="center" valign="top">
         <a href='' target="_blank" title=''>
         <img src='UploadPhoto/Image/2.gif' height="100" width="130" border="0"></a>
         </td>
         
        
         <td align="center" valign="top">
         <a href='' target="_blank" title=''>
         <img src='UploadPhoto/newsimage/20071015143853.gif' height="100" width="130" border="0"></a>
         </td>
       
        
         <td align="center" valign="top">
         <a href='' target="_blank" title=''>
         <img src='UploadPhoto/Image/2007-10/200792584956.gif' height="100" width="130" border="0"></a>
          
         </td>
       
        
         <td align="center" valign="top">
         <a href='' target="_blank" title=''>
         <img src='UploadPhoto/200791711558.gif' height="100" width="130" border="0"></a>
          
         </td>
         <td>&nbsp;</td>
        
     </TR>
   </TABLE>
   
   <!--图片列表结束--> </TD>
   <TD id="demo2" width="1"></TD>
   </TR></TBODY></TABLE>
   <SCRIPT>
   var speed=10
   demo2.innerHTML=demo1.innerHTML
   function Marquee(){
   if(demo2.offsetWidth-demo.scrollLeft<=0)
   demo.scrollLeft-=demo1.offsetWidth
   else{
   demo.scrollLeft++
   }
   }
   var MyMar=setInterval(Marquee,speed)
   demo.onmouseover=function() {clearInterval(MyMar)}
   demo.onmouseout=function() {MyMar=setInterval(Marquee,speed)}
   </SCRIPT>
  </DIV>
 </span>
</div>