var timeout = 1000;
var closetimer = 0;
var ddmenuitem = 0;

// open hidden layer
function openit(id) {
    // cancel close timer
    cancelit();

    // 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 closeit() {
    if (ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}

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

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

// close layer when click-out
document.onclick = closeit();