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;