try{
	window.addEventListener("load",imageRollover,false);
}catch(e){
	window.attachEvent("onload",imageRollover);
}

function imageRollover() {
	var images = document.images;
	var preLoadImage = new Array();
	for (var i=0; i < images.length; i++) {
		if(images[i].className == "rollover") {
			preLoadImage[i] = new Image;
			preLoadImage[i].src = images[i].src.replace("-off", "-on");
			images[i].onmouseover = function(){ this.src = this.src.replace("-off", "-on") };
			images[i].onmouseout  = function(){ this.src = this.src.replace("-on", "-off") };
		}
	}
}