function showMenu(submenu){
	switch (submenu){
		case "submenu1":
			document.getElementById("submenu1").style.visibility="visible";
			document.getElementById("submenu2").style.visibility="hidden";
//			document.getElementById("submenu3").style.visibility="hidden";
			break;
		case "submenu2":
			document.getElementById("submenu1").style.visibility="hidden";
			document.getElementById("submenu2").style.visibility="visible";
//			document.getElementById("submenu3").style.visibility='hidden';
			break;
	}
} // function show_menu()

function hideMenus(){
	document.getElementById("submenu1").style.visibility="hidden";
	document.getElementById("submenu2").style.visibility="hidden";
// 	document.getElementById("submenu3").style.visibility="hidden";
}