function KillNavMenu() {
	document.getElementById("menuoverlaycontainer1").style.display = "none";
	document.getElementById("menuoverlaycontainer2").style.display = "none";
	document.getElementById("menuoverlaycontainer3").style.display = "none";
	document.getElementById("menuoverlaycontainer4").style.display = "none";
	document.getElementById("subsection_nav").style.display = "block";
}




function DisplayNavMenu(menunumber) {
	KillNavMenu();
	document.getElementById("subsection_nav").style.display = "none";
	var menuid = "menuoverlaycontainer" + menunumber;
	document.getElementById(menuid).style.display = "block";
	var theObj = document.getElementById(menuid); 
}