function smartRollover() {  
if(document.getElementsByTagName) {  
var images = document.getElementsByTagName("img");  
var preImages = new Array();  
for(var i=0; i < images.length; i++) {  
if(images[i].getAttribute("src").match("_off.")) {  
var preImage = new Image();  
preImage.src =  
images[i].getAttribute("src").replace("_off.", "_on.");  
preImages.push(preImage);  
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);  
}