var menu_active;
var menu_timer;

function menu_close()
{
	if (menu_active)
	{
		menu_active.style.visibility = 'hidden';
	}
}

function menu_delay_cancel()
{
	if (menu_timer)
	{
		window.clearTimeout(menu_timer);
		menu_timer = null;
	}
}

function menu_delay_close()
{
	menu_timer = window.setTimeout(menu_close, 500);
}

function menu_open(id)
{
	menu_delay_cancel();
	
	if (menu_active)
	{
		 menu_active.style.visibility = 'hidden';
	}
	
	menu_active = document.getElementById(id);
	menu_active.style.visibility = 'visible';
}