/**
 * @see  utility.js#addOnload()
 * @see  utility.js#getElementsByClass()
 */
var rollover = {
	
	constructor : function() {
		var preImages = new Array();
		var targets   = getElementsByClass("rollover", document);
		
		for(var i = 0; i < targets.length; i ++) {
			if(targets[i].tagName.toLowerCase() == "img" || targets[i].tagName.toLowerCase() == "input") {
				var src  = targets[i].getAttribute("src");
				var type = src.substring(src.lastIndexOf("."), src.length);
				
				targets[i].base = src;
				targets[i].over = src.replace(type, "_on"+ type);
				targets[i].onmouseover = function() { this.setAttribute("src", this.over); };
				targets[i].onmouseout  = function() { this.setAttribute("src", this.base); };
				
				var stack = document.createElement("img");
				stack.setAttribute("src", targets[i].over);
				preImages.push(stack);
			}
		}
	}
};

addOnload(rollover.constructor);