var menuTimeout = 300;
var menuCloseTimer = 0;
var menuObject = 0;

function OpenMenu(menuID) {

    CancelScheduledClosing();

    if (menuObject) {
        menuObject.style.visibility = 'hidden';
    }

    menuObject = document.getElementById(menuID);
    menuObject.style.visibility = 'visible';
}

function CloseMenu() {
    if (menuObject) {
        menuObject.style.visibility = 'hidden';
    }
}

function ScheduleMenuClosing() {
    menuCloseTimer = window.setTimeout(CloseMenu, menuTimeout);
}

function CancelScheduledClosing() {
    if (menuCloseTimer) {
        window.clearTimeout(menuCloseTimer);
        menuCloseTimer = null;
    }
}

document.onclick = CloseMenu;