function smartRollover() {
	if(!document.getElementsByTagName) return;
	var i = 0;
	var images = document.getElementsByTagName("img");
	var inputs = document.getElementsByTagName("input");

	for(i=0; i < images.length; i++) {
		smartRolloverAddEvents(images[i]);
	}

	for(i=0; i < inputs.length; i++) {
		if(inputs[i].getAttribute("type") != "image") continue;
		smartRolloverAddEvents(inputs[i]);
	}
}

function smartRolloverAddEvents(elem) {
	if(!elem.getAttribute("src").match("_off.")) return;
	elem.onmouseover = function() {
		this.setAttribute("src", this.getAttribute("src").replace("_off.", "_on."));
	}
	elem.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);
}