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

function dropmenu_open()
{  dropmenu_canceltimer();
   dropmenu_close();
   ddmenuitem = $(this).find('ul').css('visibility', 'visible');}

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

function dropmenu_timer()
{  closetimer = window.setTimeout(dropmenu_close, timeout);}

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

$(document).ready(function()
{  $('#dropmenu > li').bind('mouseover', dropmenu_open)
   $('#dropmenu > li').bind('mouseout',  dropmenu_timer)});

document.onclick = dropmenu_close;