function smartRollover() {  
       if(document.getElementsByTagName) {  
           var images = document.getElementsByTagName("img");  
           for(var i=0; i < images.length; i++) {  
               if(images[i].getAttribute("src").match("_off."))  
              {  
                  images[i].onmouseover = function() {  
                       this.setAttribute("src", this.getAttribute("src").replace("_off.", "_on."));  
                   }  
                   images[i].onmouseout = function() {  
                      this.setAttribute("src", this.getAttribute("src").replace("_on.", "_off."));  
                  }  
              }  
           }  
       }  
  }  
   if(window.addEventListener) {  
      window.addEventListener("load", smartRollover, false);  
   }  
   else if(window.attachEvent) {  
       window.attachEvent("onload", smartRollover);  
   }