var menu = document.getElementById("mainMenu");
var middle = document.getElementById("middle");
var container = document.getElementById("contentContainer");
var menuVisible = true;

function switchMenu(){
	if (menuVisible) {
		menu.style.visibility="hidden";
		middle.style.backgroundImage="none";
		menuVisible=false;
	} else {
		middle.style.backgroundImage="url(/img/menu_border.gif)";
		menu.style.visibility="visible";
		menuVisible=true;
	}
}

switchMenu();