jquery Nestable 获取改变排序后的json数据拖动排序

<script type="text/javascript">
            jQuery(function($){
                $('.dd').nestable();
                $('.dd-handle a').on('mousedown', function(e){
                    e.stopPropagation();
                });
                $('[data-rel="tooltip"]').tooltip();
                 $('#nestable').nestable().on('change', function(){ 
                     var r = $('.dd').nestable('serialize'); 
                     $("#xx").html(JSON.stringify(r));  //改变排序之后的数据
                });
                 $('#nestable').nestable().on('change', updateOutput);
            });
        </script>

　　以上代码用来获取操作后的json 数据，传递给后台，进行数据排序处理。

以下为我的操作：

<script type="text/javascript">
    jQuery(function($){
        var courseID = '{$course_id}';
        $('.dd').nestable();
        $('.dd-handle a').on('mousedown', function(e){
            e.stopPropagation();
        });
        $('[data-rel="tooltip"]').tooltip();
        $('#nestable').nestable().on('change', function(){
            var r = $('.dd').nestable('serialize');
 
            console.log(11);
            console.log(JSON.stringify(r));
            $.ajax({
                type: 'POST',
                url: "__URL__/updateSort",
                data: {jsonData:JSON.stringify(r),courseId:courseID},
                success:function(result){
                    //console.log(result);
                    window.location.reload();
                }});
            $("#xx").html(JSON.stringify(r));   //改变排序之后的数据
        });
        $('#nestable').nestable().on('change', updateOutput);
    });
</script>

public function updateSort(){
    //$data = '[{"id":605,"children":[{"id":4093},{"id":4095},{"id":4094},{"id":4096},{"id":4097},{"id":4098},{"id":4099},{"id":4100},{"id":4101},{"id":4102},{"id":4103},{"id":4104},{"id":4105},{"id":4106},{"id":4107},{"id":4108},{"id":4109},{"id":4110},{"id":4111},{"id":4112}]}]';
    $data = $_POST['jsonData'];
    //$data = '[{"id":553,"children":[{"id":3769},{"id":3768},{"id":3770},{"id":3771},{"id":3772},{"id":3773},{"id":3774},{"id":3775},{"id":3776},{"id":3777},{"id":3778}]}]';
    $data = json_decode($data);
    //var_dump($data);
    $courseId = $_POST['courseId'];
    //$courseId = 343;
    $chapterId = $data[0]->id;
    //$chapterId = 553;
    $childrenData = $data[0]->children;
 
    try{
        foreach($childrenData as $key=>$item){
            echo $item->id."--".$key."<br/>";
            M('CourseChapterSection')->where(array('course_id'=>$courseId,'chapter_id'=>$chapterId,'section_id'=>$item->id))->data(array('s_sort'=>$key))->save();
        }
        echo 1;
    }catch(\Exception $e){
        echo 0;
    }
}