var timeout    = 500;
var closetimer = 0;
var ddmenuitem = 0;
function menu_open()
{
  menu_canceltimer();
  menu_close();
  ddmenuitem = $(this).find('ul').css('visibility', 'visible');
}

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;
    }
}