var hidemenutimer;
var currentmenu;

function openmenu(menuid) {
    cancelclosetimer();
    if (currentmenu) {
        currentmenu.style.visibility = 'hidden';
    }
    currentmenu = document.getElementById(menuid);
    currentmenu.style.visibility = 'visible';
}

function closemenu() {
    if (currentmenu) {
        currentmenu.style.visibility = 'hidden';
        currentmenu = null;
    }
}

function closemenu_starttimer() {
    hidemenutimer = window.setTimeout('closemenu();', 500)
}

function cancelclosetimer() {
    if (hidemenutimer) {
        window.clearTimeout(hidemenutimer);
        hidemenutimer = null;
    }
}