$(document).ready( 
 
 function()
 
 {
 
 
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;
 
 
});