var images_loaded = false;
 var img_normal = new Array();
 var img_over = new Array();

 function rolloverInit()
 {
   images_loaded = false; 
 }

 function rolloverReady()
 {
   images_loaded = true; 
 }
     
 function loadImage(index, imgoff, imgon) 
 {
   img_normal[index] = new Image();
   img_over[index] = new Image();
   img_normal[index].src = imgoff;
   img_over[index].src = imgon; 
 }

 function doRollOver( ButtonName, arrNumber ) 
 {
  if (images_loaded) document[ButtonName].src = img_over[arrNumber].src;  

 }

 function doRollOut( ButtonName, arrNumber ) 
 {
  if (images_loaded) document[ButtonName].src = img_normal[arrNumber].src;
 }