window.onload=function(){

 findimg();

}



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(/_on/.test(src))

 {

  newsrc = src.replace('_on','');

 }else{

  newsrc = src.replace(ftype, '_on'+ftype);

 }

 o.childNodes[isnode].src=newsrc;

}