Event.observe(window, "load", function(){
$$(".onM").each(function(el){
	el.observe("mouseover",function(){
		new Effect.Opacity(el, { from: 1, to: 0.5,duration: 0.3 });
	});
	el.observe("mouseout",function(){
		new Effect.Opacity(el, { from: 0.5, to:1,duration: 0.3 });
	});
});
});