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);  
}