var menu = function(){
	var that = {};
	var menu = {
		"menu_top":{},
		"menu_binfo":{},
		"menu_access":{},
		"menu_museum":{"submenu":true},
		"menu_minfo":{"submenu":true},
		"menu_content":{"submenu":true}
	};

	var menuFocusOn = function(ele){
		var eleMenuImg = ele.getElementsByTagName("img")[0];
		eleMenuImg.src = eleMenuImg.src.replace(/_off\.gif$/g,"_on\.gif");
		//eleMenuImg.src = "./img/menu/menubar_"+ele.id.slice(5)+"_on.gif"
		if(menu[ele.id].hasOwnProperty("submenu")){
			var eleSubMenu = ele.getElementsByTagName("ul")[0];
			eleSubMenu.style.display = "block";
		}
	};
	var menuFocusOff = function(ele){
		var eleMenuImg = ele.getElementsByTagName("img")[0];
		eleMenuImg.src = eleMenuImg.src.replace(/_on\.gif$/g,"_off\.gif");
		//eleMenuImg.src = "./img/menu/menubar_"+ele.id.slice(5)+"_off.gif"
		if(menu[ele.id].hasOwnProperty("submenu")){
			var eleSubMenu = ele.getElementsByTagName("ul")[0];
			eleSubMenu.style.display = "none";
		}
	};
	var linkItems = function(){
		for(var i in menu){
			var eleMenuItem = document.getElementById(i);
			eleMenuItem.onmouseover =  (function(eleMenuItem){
				return function(){
					menuFocusOn(eleMenuItem);
				};
			})(eleMenuItem);

			eleMenuItem.onmouseout =  (function(eleMenuItem){
				return function(){
					menuFocusOff(eleMenuItem);
				};
			})(eleMenuItem);
		}
	};

	that.linkItems = linkItems;
	return that;
};

var menuview = menu();
window.onload = (function(){
	return function(){
		menuview.linkItems();
	};
})();