jQuery(document).ready(function($) {
  // Code using $ as usual goes here.
  $('ul.sub').hide();
  
  $('a.sub').click(function(event){
  	event.preventDefault();
        // check that the menu is not currently animated
        if ($('#navigation ul:animated').size() == 0) {
            // create a reference to the active element (this)
            // so we don't have to keep creating a jQuery object
            $heading = $(this).parent();
            // create a reference to visible sibling elements
            // so we don't have to keep creating a jQuery object
            $expandedSiblings = $heading.siblings().find('ul:visible');
            if ($expandedSiblings.size() > 0) {
                $expandedSiblings.slideUp(500, function(){
                    $heading.find('ul').slideDown(500);
                });
            }
            else {
                $heading.find('ul').slideDown(1000);
            }
        }
    });
});