var timeout    = 50;
var closetimer = 0;
var ddmenuitem = 0;

function top_nav_open()
{  top_nav_canceltimer();
   top_nav_close();
   ddmenuitem = jQuery(this).find('ul').css('visibility', 'visible');}

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

function top_nav_timer()
{  closetimer = window.setTimeout(top_nav_close, timeout);}

function top_nav_canceltimer()
{  if(closetimer)
   {  window.clearTimeout(closetimer);
      closetimer = null;}}
	 
function top_nav_doOpen()
{ jQuery(this).addClass("hover");
        jQuery('ul:first',this).css('visibility', 'visible');
    }
	  

jQuery(document).ready(function()
{  jQuery('#top_nav > li').bind('mouseover', top_nav_open)
   jQuery('#top_nav > li').bind('mouseout',  top_nav_timer)});

document.onclick = top_nav_close;