//rollover

function RollImg() {
	if(document.getElementsByTagName) {
		var naviImg = document.getElementsByTagName("img");
		
		for(var i=0; i < naviImg.length; i++) {
			if(naviImg[i].getAttribute("src").match("_off.")){
					naviImg[i].onmouseover = function() {
					this.setAttribute("src", this.getAttribute("src").replace("_off.", "_on."));
				}
						naviImg[i].onmouseout = function() {
						this.setAttribute("src", this.getAttribute("src").replace("_on.", "_off."));
				}
			}
		}
	}
}

if(window.addEventListener) {
	window.addEventListener("load", RollImg, false);

}else if(window.attachEvent) {
	window.attachEvent("onload", RollImg);
}