var timeout	= 500;
var closetimer	= 0;
var menuitem	= 0;

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

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

	// get new layer and show it
	menuitem = document.getElementById(id);
	menuitem.style.visibility = 'visible';

}

// close showed layer
function mclose() {
	if(menuitem) menuitem.style.visibility = 'hidden';
}

// go close timer
function menuclose() {
	closetimer = window.setTimeout(mclose, timeout);
}

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

// close layer when click-out
document.onclick = mclose;