var openmenu = null;
var menuclosetimer = null;
var timeout = 500;

function mclosetimer() {
        menuclosetimer = window.setTimeout(mclose, timeout);
}

function cancelclosetime() {
        if (menuclosetimer) {
                window.clearTimeout(menuclosetimer);
                menuclosetimer = null;
        }
}

function mopen(mid) {
        cancelclosetime();

        if (openmenu != null) {
                mclose();
        }

        var mn = document.getElementById(mid);
        mn.style.visibility='visible';
        openmenu = mn;
}

function mclose() {
        openmenu.style.visibility='hidden';
        openmenu = null;
}