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);
}