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);
	if(ddmenuitem) { 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;