$(function()
      {
$('li:has(ul)') 
           .click(function(event){
            if (this == event.target) {
               $('li:has(ul)').children().hide('slow'); 
               $(this).children().animate({opacity:'toggle',height:'toggle'},'slow'); 
                                      }
                     return false;
                                 }
                   )
           .children().hide();
       }
 );