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

function nav_open() {
    nav_canceltimer();
    nav_close();
    ddmenuitem = $(this).find('ul').eq(0).css('visibility', 'visible');
}

function nav_close()
{ if (ddmenuitem) ddmenuitem.css('visibility', 'hidden'); }

function nav_timer()
{ closetimer = window.setTimeout(nav_close, timeout); }

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

$(document).ready(function () {
    $('#nav > li').bind('mouseover', nav_open);
    $('#nav > li').bind('mouseout', nav_timer);
});

document.onclick = nav_close;