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

function menuOpen(id)
{	
menuResetTimer();

if(ddmenuitem)
 ddmenuitem.style.visibility = 'hidden';

ddmenuitem = document.getElementById(id);
ddmenuitem.style.visibility = 'visible';
}

function menuClose()
{
if(ddmenuitem)
 ddmenuitem.style.visibility = 'hidden';
}

function menuKillTimer()
{
closetimer = window.setTimeout(menuClose, timeout);
}

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

document.onclick = menuClose;