function initRollover(){
	var img = document.getElementsByTagName("img");
	for(var i = 0; i < img.length; i++){
		if(img[i].className == "rollover"){
			function onMouse(){
				var src = this.getAttribute("src");
				var name = src.substring(0, src.lastIndexOf("."));
				var type = src.substr(src.lastIndexOf("."));
				var newSrc = name + "_on" + type;
				this.setAttribute("src", newSrc);
			};
			function outMouse(){
				var src = this.getAttribute("src");
				var name = src.substring(0, src.lastIndexOf("_"));
				var type = src.substr(src.lastIndexOf("."));
				var newSrc = name + type;
				this.setAttribute("src", newSrc);
			};
			img[i].onmouseover = onMouse;
			img[i].onmouseout =	 outMouse;
		}
	}
}