function rollover() {
	var images = document.getElementsByTagName('img');
	for(var i=0; i < images.length; i++) {
	if(images[i].className == 'on') {
	var iFle = images[i].getAttribute('src');
	var iFit = iFle.substring(iFle.lastIndexOf('.'), iFle.length);
	var iRep = iFle.replace(iFit, '_on' +iFit);
	images[i].setAttribute('iRep', iRep);
		images[i].onmouseover = function() {
			this.setAttribute('src', this.getAttribute('iRep'));
		}
		images[i].onmouseout = function() {
			this.setAttribute('src', this.getAttribute('src').replace('_on' +iFit, iFit));
		}
	}
	}
}

if(window.addEventListener) {
	window.addEventListener('load',rollover,false);
} else if(window.attachEvent) {
	window.attachEvent('onload',rollover);
}