var timeout	= 500;
var timer	= 0;
var submenu	= 0;

// open hidden layer
function menuopen(id)
{
	// cancel close timer
	timemenucancelclose();

	// close old submenu layer
	if(submenu) submenu.style.visibility = 'hidden';

	// new submenu layer
	submenu = document.getElementById(id);
	submenu.style.visibility = 'visible';

}
// close submenu
function menuclose()
{
	if(submenu) submenu.style.visibility = 'hidden';
}

function timemenuclose()
{
	timer = window.setTimeout(menuclose, timeout);
}

// cancel close submenu
function timemenucancelclose()
{
	if(timer)
	{
		window.clearTimeout(timer);
		timer = null;
	}
}

// click-out submenu close
document.onclick = menuclose;