I have some javascript on a page which scrolls through customer quotes. It works in Firefox 3 and Safari, but not in IE7 or Opera. Can anyone tell me why that would be?

Here's the code:

Code:
var marqueewidth="190px"
var marqueeheight="150px"
var marqueespeed=-20
//Pause marquee onMousever (0=no. 1=yes)?
var pauseit=1  


//Specify the marquee's content
//Keep all content on ONE line, and backslash any single quotations (ie: that\'s great):
var scrolling = new Array();
scrolling[0] ='<p><img src="/images2/quotes/gbc.jpg" border="0" ></p>'
scrolling[1] ='<p><img src="/images2/quotes/casagrande.jpg" border="0" ></p>'
scrolling[2] ='<p><img src="/images2/quotes/energy.jpg" border="0" ></p>'
scrolling[3] ='<p><img src="/images2/quotes/northwest.jpg" border="0" ></p>'
scrolling[4] ='<p><img src="/images2/quotes/stannah.jpg" border="0" ></p>'
scrolling[5] ='<p><img src="/images2/quotes/venice.jpg" border="0" ></p>'
scrolling[6] ='<p><img src="/images2/quotes/farner.jpg" border="0" ></p>'
scrolling[7] ='<p><img src="/images2/quotes/gardner.jpg" border="0" ></p>'
scrolling[8] ='<p><img src="/images2/quotes/haley.jpg" border="0" ></p>'
scrolling[9] ='<p><img src="/images2/quotes/hayes.jpg" border="0" ></p>'
scrolling[10] ='<p><img src="/images2/quotes/imi.jpg" border="0" ></p>'
scrolling[11] ='<p><img src="/images2/quotes/midland.jpg" border="0" ></p>'
scrolling[12] ='<p><img src="/images2/quotes/prettl.jpg" border="0" ></p>'



marqueespeed=(document.all)? marqueespeed : Math.max(1, marqueespeed-10) //slow speed down by 1 for NS
var copyspeed=marqueespeed
var pausespeed=(pauseit==0)? copyspeed: 0
var iedom=document.all||document.getElementById
var actualheight=''
var cross_marquee, ns_marquee
function getstartpos(istr,iend){
   var seed = Math.random(); //0-1
   seed = Math.round(seed*iend);
   return seed;

}
function getImages(){
   var len = scrolling.length;
   var start = getstartpos(0,len);
   var newstr = '';
   for( var i=start;i<len; i++)
      newstr += scrolling[i]; 
   for( var i=0;i<start; i++)
      newstr += scrolling[i]; 

   return newstr;
} 
function getmarqueecontent(){
   var marqueecontent='<font face="Verdana, helvetica, sans-serif" size="1">'
                      + getImages()
                      +'</font>'
   return marqueecontent; 
}
function populate(){
if (iedom){
cross_marquee=document.getElementById? document.getElementById("iemarquee") : document.all.iemarquee
cross_marquee.style.top=parseInt(marqueeheight)+8+"px"
cross_marquee.innerHTML=getmarqueecontent();
actualheight=cross_marquee.offsetHeight
}
else if (document.layers){
ns_marquee=document.ns_marquee.document.ns_marquee2
ns_marquee.top=parseInt(marqueeheight)+8
ns_marquee.document.write(marqueecontent)
ns_marquee.document.close()
actualheight=ns_marquee.document.height
}
lefttime=setInterval("scrollmarquee()",20)
}
window.onload=populate


function scrollmarquee(){

if (iedom){
if (parseInt(cross_marquee.style.top)>(actualheight*(-1)+8))
cross_marquee.style.top=parseInt(cross_marquee.style.top)-copyspeed+"px"
else
cross_marquee.style.top=parseInt(marqueeheight)+8+"px"
}
else if (document.layers){
if (ns_marquee.top>(actualheight*(-1)+8))
ns_marquee.top-=copyspeed
else
ns_marquee.top=parseInt(marqueeheight)+8
}
}

if (iedom||document.layers){
with (document){
if (iedom){
write('<div style="position:absolute;width:'+marqueewidth+';height:'+marqueeheight+';top:150px;right:5px;overflow:hidden" onMouseover="copyspeed=pausespeed" onMouseout="copyspeed=marqueespeed">')
write('<div id="iemarquee" style="position:absolute;left:0px;top:0px;width:100%;">')
write('</div></div>')
}
else if (document.layers){
write('<ilayer width='+marqueewidth+' height='+marqueeheight+' name="ns_marquee">')
write('<layer name="ns_marquee2" width='+marqueewidth+' height='+marqueeheight+' left=0 top=0 onMouseover="copyspeed=pausespeed" onMouseout="copyspeed=marqueespeed"></layer>')
write('</ilayer>')
}
}
}