我在工作的项目，使用一个动态或相关的下拉列表codeigniter。这是我的noob逻辑，视图中的国家值传递给模型，然后模型从视图中获取具有相同国家值的状态数据，然后控制器从该模型中获取状态数据并再次传递给视图。问题是状态下拉列表什么都不显示。对不起，我是新来的。

//This is the Controllers (Pkl.php)
$data['all_country'] = $this->Server_Model->get_country_model();
$data['all_state'] = $this->Server_Model->get_state_model();
$this->load->view('contents/page_dashboard', $data);

//This is the Models (Server_Model.php)
function get_country_model(){
            $db_jarlap = $this->load->database('gis_bali', TRUE);
            $db_jarlap->select("*");
            $db_jarlap->from("country");
            $que = $db_jarlap->get();
            return $que->result();
        }
function get_state_model(){
            $kakakoko = filter_input(INPUT_POST, 'country_id');
            $db_jarlap = $this->load->database('gis_bali', TRUE);
            $db_jarlap->select("*");
            $db_jarlap->from("state");
            $db_jarlap->where(" id_country = $kakakoko ");
            $que = $db_jarlap->get();
            return $que->result();
        }

//This is the Views Content (page_dashboard.php)
<script src="<?php echo base_url() ?>resources/js/jquery-3.3.1.min.js"</script>
<script>
            $(document).ready(function(){
            $('#formCountry').change(function(){
                  var country_id = $(this).val();

                  $.ajax({
                            url: "<?php echo base_url() ?            >application/models/Server_Model.php",
                        method: "POST", 
                        data: {country_id:country_id}, 
                        success: function(data) { 
                        $('#formState').html(data);
                                            }
                                    });
                                });
                            });
</script>

<select name="formCountry" id="formCountry">
<?php foreach($all_country as $semua_country): ?>
<option value="<?php echo $semua_country->id_country; ?>"><?php echo     $semua_country->nama_country; ?></option>
<?php endforeach; ?>
</select>

<select name="formState" id="formState" >
<?php foreach($all_state as $semua_state): ?>
<option value="<?php echo $semua_state->id_state; ?>"><?php echo $semua_state->nama_state; ?></option>
<?php endforeach; ?>
</select>

谢谢你的帮助。