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

function jsddm_open()
{
  jsddm_canceltimer();
  ddmenuitem = $(this).find('ul').eq(0).slideDown();
}

function jsddm_close()
{ 
  if(ddmenuitem) ddmenuitem.slideUp();
}

function jsddm_timer()
{
  closetimer = window.setTimeout(jsddm_close, timeout);
}

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

$(document).ready(function(){
  $('#topnav > li').bind('mouseover', jsddm_open);
  $('#topnav > li').bind('mouseout',  jsddm_timer);
});

document.onclick = jsddm_close;