$(document).ready(function(){
	
	$("ul.menu li").each(function(){
		
		$(".menu_l").css("background-image","none");
		$(".menu_r").css("background-image","none");
		
	});
	
	jQuery.each([1,2,3,4],function(index, item) {
		
		$("#m"+item+"_2").hover(function(){
		$("#m"+item+"_1").css("background","url(images/menu_l.png) no-repeat");
		$("#m"+item+"_3").css("background","url(images/menu_r.png) no-repeat");
		}, function() { 
		$(".menu_l").css("background-image","none");
		$(".menu_r").css("background-image","none");
		});
	});
	
});