var timeout = 100;
    var closetimer = 0;
    var ddmenuitem = 0;

    // open hidden layer
    function mopen(id) 
    {
        // cancel close timer
        mcancelclosetime();

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

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

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

    // close layer when click-out
    document.onclick = mclose;