var menu_timeout    = 500;
var menu_closetimer = 0;
var menu_mainmenuitem = 0;

function mainmenu_open() {  
   mainmenu_canceltimer();
   mainmenu_close();
   menu_mainmenuitem = jQuery(this).find('ul').css('visibility', 'visible');
}
function mainmenu_close() {  
  if(menu_mainmenuitem) menu_mainmenuitem.css('visibility', 'hidden');
}

function mainmenu_timer() {  
  menu_closetimer = window.setTimeout(mainmenu_close, menu_timeout);
}
function mainmenu_canceltimer() {  
  if(menu_closetimer) {  
    window.clearTimeout(menu_closetimer);
    menu_closetimer = null;
  }
}
document.onclick = mainmenu_close;

/* Document Ready, Perform jQuery actions */
$(document).ready(function() {
  $("#mainmenu > li").bind("mouseover", mainmenu_open);
  $("#mainmenu > li").bind("mouseout",  mainmenu_timer);
});