Event.observe(window,'load',addRollovers);


function addRollovers(ev){
	var rollovers = $(document).getElementsByClassName('rollover');
	for(var i in rollovers){
		var ro= rollovers[i];
		Event.observe(ro,'mouseover',onRollover);
		Event.observe(ro,'mouseout',onRollout);
	} 
}

function onRollover(el){
	var e = Event.element(el);
	e.src='/img/'+e.id+'_over.gif';
}
function onRollout(el){
	var e = Event.element(el);
	e.src='/img/'+e.id+'.gif';
}