var lastMenu = null;

function swapMenu(menuName) {
	if (lastMenu) {
		document.getElementById(lastMenu).style.visibility = 'hidden';
		document.getElementById(lastMenu).style.display = 'none';
	}
	if (menuName) {
		document.getElementById(menuName).style.visibility = 'visible';
		document.getElementById(menuName).style.display = 'block';
		document.getElementById(menuName).style.zIndex = 255;
		lastMenu = menuName;
	}
}