$(document).ready(function() {
    $('#DropDownMenu > li').bind('mouseover', menu_open);
    $('#DropDownMenu > li').bind('mouseout', menu_timer);

    document.onclick = menu_close;

});

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

function menu_open()
{
    menu_canceltimer();
    menu_close();
    ddmenuitem = $(this).find('ul').css('visibility', 'visible');
    $(this).find('ul').css('display', 'block');
}

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

function menu_timer()
{
    closetimer = window.setTimeout(menu_close, timeout);
}

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