var timeout         = 500;
var closetimer		= 0;
var ddmenuitem      = 0;

// open hidden layer
function mopen(id) {
	// cancel close timer
	mcancelclosetime();
	// close old layer
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
	// get new layer and show it
	ddmenuitem = document.getElementById(id);
	ddmenuitem.style.visibility = 'visible';

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

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

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

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