var timeout = 500;
var closetimer = 0;
var ddmenuitem = 0;

function mopen(id)
{
    mcancelclosetime();

    if (ddmenuitem)
        ddmenuitem.style.visibility = 'hidden';

    ddmenuitem = document.getElementById(id);
    ddmenuitem.style.visibility = 'visible';
}

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

function mclosetime()
{
    closetimer = window.setTimeout(mclose, timeout);
}

function mcancelclosetime()
{
    if (closetimer) {
        window.clearTimeout(closetimer);
        closetimer = null;
    }
}

document.onclick = mclose;