$(document).ready
(function(){
		$(".simplenav>ul>li").each(function(){
			initialiseNav(this);
		});
		
		$(".simplenav>ul>li>a").bind("mouseenter",function(){
			hideAllNav();
			showChildNav(this);
		});
		
		$(".simplenav").bind("mouseleave",function(){
			hideAllNav();
			showCurrentNav();
		});
	});

	function initialiseNav(navitem){
		//centre of this button
		var widthone = 0;
		widthone = $(navitem).outerWidth();
		widthone = widthone/2;
		
		$(navitem).prevUntil('ul').each(function() {
			widthone = widthone + ($(this).outerWidth());
		});
		
		//width of subnav
		var widthtwo = 0;
		$(navitem).find("li").each(function() {
			widthtwo = widthtwo + ($(this).outerWidth());
		});
		widthtwo = widthtwo/2;
		
		//calculate margin
		var marginvalue = 0;
		marginvalue = widthone - widthtwo;
		
		if(marginvalue>0){
			//set left margin of first subnav item only if it isn't negative
			$(navitem).children("ul").find("li").first().css("margin-left", marginvalue);
		}
	}

	function hideAllNav(menu){
		$(".simplenav ul ul").removeClass("on fix");
		$(".simplenav ul ul").addClass("off");
	}
	
	function showChildNav(actOnMe){
		$(".simplenav li").removeClass("MenuVisible");
		$(actOnMe).parent("li").find("ul").removeClass("off");
		$(actOnMe).parent("li").find("ul").addClass("on fix");
		$(actOnMe).parent("li").not($("li.here")).find("ul").bind("mouseenter",function(){
			$(this).parent("li").addClass("MenuVisible");
			
		}).bind("mouseleave",function(){
			$(this).parent("li").removeClass("MenuVisible");
		});
	}
	
	function showCurrentNav(){
		//only do this if it is currently hidden
		if($(".simplenav li.here ul").hasClass("off")){
			$(".simplenav li.here ul").removeClass("off");
			$(".simplenav li.here ul").addClass("on fix");
		}
	}