function SwitchMenu(id) {
	
	var obj = 'sub' + id;
	var el = document.getElementById(obj);
	var ar = document.getElementById('nav').getElementsByTagName('span');

		if (el.style.display != 'block')
		{
			for (var i = 0; i < ar.length; i++)
			{
				if (ar[i].classname == 'submenu')
				{
					ar[i].style.display = 'none';
				}
			}

			el.style.display = 'block';

		} else {
			el.style.display = 'none';
		}
}