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

// open hidden layer
function mopen(id)
{	
	mcancelclosetime();// cancel close timer
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';// close old layer

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

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

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

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

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