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

function mainNav_open() {
    mainNav_canceltimer();
    mainNav_close();
    ddmenuitem = $(this).find('ul').css('visibility', 'visible');
}

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

function mainNav_timer()
{ closetimer = window.setTimeout(mainNav_close, timeout); }

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

$(document).ready(function() {
    $('#mainNav > li').bind('mouseover', mainNav_open)
    $('#mainNav > li').bind('mouseout', mainNav_timer)
});

document.onclick = mainNav_close;