function initRollovers() {
	if (!document.getElementById) return
	
	var aPreLoad = new Array();
	var sTempSrc;
	var aImages = document.getElementsByTagName('img');

	for (var i = 0; i < aImages.length; i++) {
		if (aImages[i].className == 'imgover') {
			var src = aImages[i].getAttribute('src');
			var ftype = src.substring(src.lastIndexOf('.'), src.length);
			var hsrc = src.replace(ftype, '_on'+ftype);

			var cheackKey = src.substring(src.lastIndexOf('_on'), src.length);
			var cheackKeyArr = cheackKey.split('.');

			if(cheackKeyArr[0] != '_on'){
				aImages[i].setAttribute('hsrc', hsrc);

				aPreLoad[i] = new Image();
				aPreLoad[i].src = hsrc;
				
				aImages[i].onmouseover = function() {
					sTempSrc = this.getAttribute('src');
					this.setAttribute('src', this.getAttribute('hsrc'));
				}	
				
				aImages[i].onmouseout = function() {
					if (!sTempSrc) sTempSrc = this.getAttribute('src').replace('_on'+ftype, ftype);
					this.setAttribute('src', sTempSrc);
				}
			}
		}
	}
}

window.onload = initRollovers;