function showNav(id) {
	if (onNavId != id) {
		$('mNavImg_' + id).style.visibility = 'visible';
	}
	if ($('subNav_' + id)) {
		showSubNav(id);
	}
}

function hideNav(id) {
	if ($('subNav_' + id)) {
		hideSubNav(id);
	}
	if (onNavId != id) {
		$('mNavImg_' + id).style.visibility = 'hidden';
	}
}

function showSubNav(id) {
	document.getElementById('subNav_' + id).style.left = $('mNav_' + id).positionedOffset()[0] + 'px';
	document.getElementById('subNav_' + id).style.width = $('mNav_' + id).getWidth() + 'px';
	
	$('subNav_' + id).show();
}

function hideSubNav(id) {
	$('subNav_' + id).hide();
}