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

function menu_open(){
  menu_canceltimer();
  menu_close();
  ddmenuitem = $(this).find('ul').eq(0).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;
  }
}

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

document.onclick = menu_close;