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

function nav_open() {
    nav_canceltimer();
    nav_close();
    ddmenuitem = $(this).find("ul").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;