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

function navmain_open()
{  navmain_canceltimer();
   navmain_close();
   ddmenuitem = $(this).find('ul').css('visibility', 'visible');}

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

function navmain_timer()
{  closetimer = window.setTimeout(navmain_close, timeout);}

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

$(document).ready(function()
{  $('#navmain > li').bind('mouseover', navmain_open)
   $('#navmain > li').bind('mouseout',  navmain_timer)});

//document.onclick = navmain_close;