/*--------------
imgMouseOver  
 ---------------*/
function addEvent(elem, type, func, flg) {
	if (elem.addEventListener) {elem.addEventListener(type, func , flg);}
	else if (elem.attachEvent) {elem.attachEvent('on' + type , func);}
}

function imgRollOver(){
  var selector = "imgOver";
  var suffix = "_o";
  var preloadImg = new Array();
  var imgTag = document.getElementsByTagName("img");
  var imgOverSrc;
  
  for(var i=0;i<imgTag.length;i++){ 		
  	if(imgTag[i].className.match(selector)){
  		var src = imgTag[i].getAttribute("src");
		var ftype = src.substring(src.lastIndexOf('.'), src.length);
		var swapImgSrc = src.replace( ftype , suffix + ftype);

		imgTag[i].setAttribute('swapImgSrc', swapImgSrc);
		preloadImg[i] = new Image();
		preloadImg[i].src = swapImgSrc;

		imgTag[i].onmouseover = function() {
			imgOverSrc = this.getAttribute("src");
			this.setAttribute("src", this.getAttribute("swapImgSrc"));
		}			
		imgTag[i].onmouseout = function() {	
			if (!imgOverSrc) imgOverSrc = this.getAttribute("src").replace(suffix + ftype, ftype);		
			this.setAttribute("src", imgOverSrc);
		}
		
	 }
  }
}

addEvent(window,'load',imgRollOver,false);