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 == 'btnover') {
			var src = aImages[i].getAttribute('src');
			var ftype = src.substring(src.lastIndexOf('.'), src.length);
			var hsrc = src.replace(ftype, '_o'+ftype);

			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('_o'+ftype, ftype);
			this.setAttribute('src', sTempSrc);
			}
		}
	}
}

function addEvent ( elem, event, func ) {
	if ( elem.addEventListener ) {
		elem.addEventListener( event, func, false );
	} 
	else {
		elem.attachEvent( 'on'+event, func );
		}
}

addEvent(window,'load',	function () {initRollovers()});