function findimg()
{
 var imgs,i;
// Loop through all images, check if they contain the class roll
 imgs=document.getElementsByTagName('img');
 for(i=0;i<imgs.length;i++)
 {
  if(/roll/.test(imgs[i].className))
  {
// add the function roll to the parent Element of the image
  imgs[i].parentNode.onmouseover=function(){roll(this);};
  imgs[i].parentNode.onmouseout=function(){roll(this);};
  imgs[i].parentNode.onfocus=function(){roll(this);};
  imgs[i].parentNode.onblur=function(){roll(this);};
  }
 }
}
function roll(o)
{
 var i,isnode,src,ftype,newsrc,nownode;
// loop through all childNodes
 for (i=0;i<o.childNodes.length;i++)
 {
  nownode=o.childNodes[i];
// if the node is an element and an IMG set the variable and exit the loop
  if(nownode.nodeType==1 && /img/i.test(nownode.nodeName))
  {
   isnode=i;
   break;
  }
 }
// check src and do the rollover
 src = o.childNodes[isnode].src;
 ftype = src.substring(src.lastIndexOf('.'), src.length);
 if(/_roll/.test(src))
 {
  newsrc = src.replace('_roll','');
 }else{
  newsrc = src.replace(ftype, '_roll'+ftype);
 }
 o.childNodes[isnode].src=newsrc;
}

ev.addEvent(window,"load",findimg,false)