$(document).ready(  
 function()
 {
var timeout    = 500;
var closetimer = 0;
var ddmenuitem = 0;

function MenuDeroulant_open()
{  MenuDeroulant_canceltimer();
   MenuDeroulant_close();
   ddmenuitem = $(this).find('ul').css('visibility', 'visible');}

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

function MenuDeroulant_timer()
{  closetimer = window.setTimeout(MenuDeroulant_close, timeout);}

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

$(document).ready(function()
{  $('#MenuDeroulant > li').bind('mouseover', MenuDeroulant_open)
   $('#MenuDeroulant > li').bind('mouseout',  MenuDeroulant_timer)});

document.onclick = MenuDeroulant_close;
});