function showSubMenu(menuID) {
    document.getElementById('sub_menu1').className = 'hidden';
	document.getElementById('sub_menu2').className = 'hidden';
	document.getElementById('sub_menu3').className = 'hidden';
	document.getElementById('sub_menu4').className = 'hidden';
	document.getElementById('sub_menu5').className = 'hidden';
	document.getElementById('sub_menu6').className = 'hidden';
	document.getElementById('sub_menu8').className = 'hidden';
    document.getElementById('sub_'+menuID).className = '';
}

function closeSubMenu(menuID) {
    document.getElementById('sub_'+menuID).className = 'hidden';
}