window.onload=function () {
	var rollovers = getElementsByClass();
	for (i=0; i < rollovers.length ; i++ ){
		rollovers[i].onmouseover = over
		rollovers[i].onmouseout = out

		var imgsrc = rollovers[i].src; // this is to pre load the 'over' state images
		imgsrc = imgsrc.replace(/_out/,'_on');
		var preload = new Image();
		preload.src=imgsrc
	}
			
}

function getElementsByClass() {
	var el = new Array();
	var tags = document.getElementsByTagName('img');
	var tcl = " rollover ";
	for(i=0,j=0; i<tags.length; i++) {
		var test = " " + tags[i].className + " ";
		if (test.indexOf(tcl) != -1)
			el[j++] = tags[i];
	}
	return el;
}



function over () {
	this.src = this.src.replace(/_out/,'_on');
	return false;
}

function out () {
	this.src = this.src.replace(/_on/,'_out');  
	return false;
}