Ajax codeigniter，成功加载太快。 .done

I have only been working with ajax for under a week now trying to use it with codeigniter to create a pretty complex ajax menu system. The user can add new sections to the menu system as they work on it. I have ajax code posting to the database and on success adding it to the menu system. The problem I am having is that the code is running before the update is made to the database. So instead of getting the new menu section I just get a copy of the latest menu before making the addition. If I wait a moment and make the call manually with a button I attached with the ajax call instead of using .done this works fine.

This is my ajax call

// this is attached to my form to add a menu section
$(function(){
$('#add_category_form').submit(function(evnt){
    evnt.preventDefault(); 
    var posting = $.post(base_url+"/menu/add_category", $("#add_category_form").serialize());
    posting.done(newCategory());
    });
//calls view to generate menu section

function newCategory(){
$.ajax({
    'url' : base_url + '/' + controller + '/new_category',
    'type' : 'POST', //

    'success' : function(data){ 
        var container = $('#testcontainer'); 
        if(data){
            container.html(data);
        }
    }
});              

}

// view
<?php
$count = count($menu)+1;
        $counter=0;
                foreach ($menu as $category) {
                    $counter++;
                    if ($count == $counter) {
                    echo "menu html goes here of last menu created";
                    } 

                }

            ?>

Ajax Deferred

If you wanted to use the ajax deferred method, you would do something like this.

(function($){

   $('#add_category_form').submit(function( event ){
       event.preventDefault();

       var _data = this.serialize();

       doSomething( _data ).then(
            function( response ){},  // Success
            function( error, code){}   // Error
       );
   });

   var doSomething = function( data ){
       return $.ajax({
          url : base_url + "/menu/add_category",
          data : data,
          type : 'POST',
          dataType : 'html'
       }).promise();  
   };

}(jQuery));