var timeout = 500;
var closetimer = 0;
var item = 0;

function open_menu() {
    canceltimer();
    close_menu();
    item = $(this).find('ul').eq(0).show();
}

function close_menu() {
    if (item) item.hide();
}

function timer() {
    closetimer = window.setTimeout(close_menu, timeout);
}

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

$(document).ready(function() {
    $('#menu > div').bind('mouseover', open_menu);
    $('#menu > div').bind('mouseout',  timer);
});

document.onclick = close_menu;