/*
*	Image rollover js
*	Author : Kazuhito Hokamura
*	http://webtech-walker.com/
*
*	Licensed under the MIT License:
*	http://www.opensource.org/licenses/mit-license.php
*/

(function(){
	function rollover(){
		var targetClassName="hoverImg";
		var suffix="_ov";

		var overReg=new RegExp("^(.+)(\\.[a-z]+)$");
		var outReg=new RegExp("^(.+)" + suffix + "(\\.[a-z]+)$");

		var preload=new Array();
		var images=document.getElementsByTagName("img");

		for (var i=0, il=images.length; i < il; i++) {
			var classStr=images[i].getAttribute("class") || images[i].className;
			var classNames=classStr.split(/\s+/);
			for(var j=0, cl=classNames.length; j < cl; j++){
				if(classNames[j]== targetClassName){

					//preload
					preload[i]=new Image();
					preload[i].src=images[i].getAttribute("src").replace(overReg, "$1" + suffix + "$2");

					//mouseover
					images[i].onmouseover=function() {
						this.src=this.getAttribute("src").replace(overReg, "$1" + suffix + "$2");
					}

					//mouseout
					images[i].onmouseout=function() {
						this.src=this.getAttribute("src").replace(outReg, "$1$2");
					}
				}
			}
		}
	}

	function addEvent(elem,event,func){
		if(elem.addEventListener) {
			elem.addEventListener(event, func, false);
		}else if(elem.attachEvent) {
			elem.attachEvent("on" + event, func);
		}
	}
	addEvent(window,"load",rollover);
})();