var m;

	function on(map)
	{
		var m2 = document.getElementById('mapacr-'+map);
		if (m == m2) return;
		
		off();
		m = m2;
		m.style.visibility = 'visible';
	}

	function off()
	{
		if (m) m.style.visibility = 'hidden';
		m = null;
		
			$(this).stop().animate({
				opacity: 0
			}, 'slow');
	}