我想请教个小问题

以下一段代码在IE浏览器里显示正常
为什么在firefox里去无法显示?
请帮忙解决一下,再些深表谢意!!!

  <table  width="200" height="219" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center" valign=middle><IMG id=image1
style="FILTER: revealTrans(Duration=4.0, Transition=1); VISIBILITY: hidden"
src="images/001.jpg" border=0></td>
<SCRIPT>
var imgs = new Array(3);
imgs[0] = "images/001.jpg";
imgs[1] = "images/002.jpg";
imgs[2] = "images/003.jpg";
imgs[3] = "images/004.jpg";
var maximg =  4;
curimg = -1;
function renderit(){
transition = Math.floor(Math.random()*23);
image1.filters.item(0).apply();
image1.filters.item(0).transition =transition;
image1.style.visibility = "";
image1.filters(0).play(2.0);
}

function switchit(){
    if(typeof(image1)!='undefined' && image1 !=null){
image1.style.visibility="hidden";
curimg++;
if( curimg>= maximg) curimg = 0;
image1.src=imgs[curimg];
renderit();
setTimeout(switchit,5000);
    }
}
switchit();
</SCRIPT>
</tr>
 </table>

把script中的image1改成document.getElementById("iamage1")