js写的无间隔滚动条(类似Marquee)ie正常 火狐(FireFox)不滚动

这是HTML代码，和JSvar w,h,id,speed,Html
w="900";//-------滚动容器的宽度--------//
h="170";//-------滚动容器的高度--------//
id="div1";//-------滚动容器的id--------//
direction="left";//-------滚动方向有四个值left，right，up，down，自己试试--------//
speed="100";//-------滚动速度100相当于1秒，越小越快-------- //
imgDiv="img";//-------放图片的容器id--------//
HtmlL=document.getElementById(imgDiv).innerHTML;
HtmlT=document.getElementById(id).innerHTML;
switch (direction)
{
case "left":
     document.getElementById(imgDiv).innerHTML=HtmlL+HtmlL;
  break;
case "right":
     document.getElementById(imgDiv).innerHTML=HtmlL+HtmlL;
  break;
case "up":
     document.getElementById(id).innerHTML=HtmlT+HtmlT;
  break;
case "down":
     document.getElementById(id).innerHTML=HtmlT+HtmlT;
  break;
}
function ss(){
document.getElementById(id).style.width=w;
document.getElementById(id).style.height=h;
document.getElementById(imgDiv).style.width=w*2;
document.getElementById(imgDiv).style.height=h;
var ele
ele=document.getElementById("div1");
switch (direction)
{
case "left":
ele.scrollLeft=ele.scrollLeft+5;
if (ele.scrollLeft>=w)
{
ele.scrollLeft=0;
}
break;
case "right":
ele.scrollLeft=ele.scrollLeft-5;
if (ele.scrollLeft<=0)
{
ele.scrollLeft=w;
}
break;
case "up":
ele.scrollTop=ele.scrollTop+5;
if (ele.scrollTop>=h)
{
ele.scrollTop=0;
}
break;
case "down":
ele.scrollTop=ele.scrollTop-5;
if (ele.scrollTop<=0)
{
ele.scrollTop=h;
}
break;
}
t=setTimeout("ss()",speed);
}
function stop(){
document.getElementById("div1").scrollLeft=document.getElementById("div1").scrollLeft;
document.getElementById("div1").scrollTop=document.getElementById("div1").scrollTop;
     clearTimeout(t);
}
setTimeout("ss()",100);
<DIV class=mBox>
<CENTER>
    <div id="div1" style="overflow:hidden; cursor:hand; margin-top:5px;" onMouseOver="stop()" onMouseOut="ss()"><UL class=mItem id="img">
        <li><DIV><A href="#" target=_blank><img alt=降压治疗新趋势 src="newImages/132.JPG" /></A></DIV><A href="#" target=_blank>降压治疗新1趋势</A></li>
        <li><DIV><A href="#" target=_blank><img alt=降压治疗新趋势 src="newImages/132.JPG" /></A></DIV><A href="#" target=_blank>降压治疗新1趋势</A></li>
</UL>
</div>
</CENTER>
<script type='text/javascript' src='newimages/gd.js'></script>
        </DIV>