function display_menu (menuid) {
	var nav = document.getElementById("nav_"+menuid);
	var subnav = document.getElementById("subnav_"+menuid);
	var allnavs = document.getElementsByName("nav");
	var allsubnavs = document.getElementsByName("subnav");
	
	
	for (var i=0; i<allnavs.length; i++) {
		allnavs[i].src = navimgd+allnavs[i].id+".gif";
	}
	for (var i=0; i<navpoints.length; i++) {
		var cur = document.getElementById("subnav_"+navpoints[i]);
		if (cur) {
			cur.style.display = "none";
			cur.style.visibility = "hidden";
		}
	}
	nav.src = navimgd+"nav_"+menuid+"_active.gif";
	subnav.style.display = "block";
	subnav.style.visibility = "visible";
}