function mainmenu() {
	subMenu("courses-menu", "courses");
	subMenu("degrees-menu", "degrees");
	subMenu("dl-menu", "dl");
	subMenu("after-menu", "after");
	subMenu("res-menu", "res");
	subMenu("help-menu", "help");

	if (document.getElementById("courses-page") == null)
		document.getElementById("courses-menu").style.display = "none";
	if (document.getElementById("degrees-page") == null)
		document.getElementById("degrees-menu").style.display = "none";
	if (document.getElementById("dl-page") == null)
		document.getElementById("dl-menu").style.display = "none";
	if (document.getElementById("after-page") == null)
		document.getElementById("after-menu").style.display = "none";
	if (document.getElementById("res-page") == null)
		document.getElementById("res-menu").style.display = "none";
	if (document.getElementById("help-page") == null)
		document.getElementById("help-menu").style.display = "none";

}

if (!document.getElementById)
    document.getElementById = function() { return null; }

	function subMenu(menuId, actuatorId) {
	    var menu = document.getElementById(menuId);
	    var actuator = document.getElementById(actuatorId);
	
	    actuator.onclick = function() {	
			if ( menu.style.display == "none") {
				menu.style.display = "block";
				}
			else {
				menu.style.display = "none";
				}
			}
		}