var previous_menu         = null;
var verberg_submenu_timer;

function toonSubMenu(id)
{	
	clearTimeout(verberg_submenu_timer);
	
	var menu_item_obj           = document.getElementById("menu_" + id);
	
	var position                = geefObjectPositie(menu_item_obj);
	
	var submenu_item_obj        = document.getElementById("submenu_" + id);

	if(previous_menu != null && previous_menu != menu_item_obj)
	{
		previous_menu.style.visibility = "hidden";
	}		
	
	if(submenu_item_obj != null)
	{
		submenu_item_obj.style.top  = (32 + "px");
	
		submenu_item_obj.style.left = (-8 + "px");
		
		submenu_item_obj.style.visibility = "visible";
	}
	
	previous_menu = submenu_item_obj;
}

function verbergSubMenu()
{
	clearTimeout(verberg_submenu_timer);
	
	verberg_submenu_timer = setTimeout("previous_menu.style.visibility = 'hidden';", 1000);
}