我想建立更新表單當我改變主下拉菜單，然後更新第二個下拉列表

Question

     <div> 
         <label for="form-field-select-3">State : </label> 
         <br /> 
         <select class="chosen-select form-control" id="State" name="State" data-placeholder="Choose a State..."> 
          <option value="0"> </option> 
          <?php 
          $query=$this->db->query("select Address_State from ref_address_state where Address_State_ID='".$property->State_ID."'"); 
          $query=$query->row(); 
          foreach($Address_State as $rows) 
          { 
           if($rows['Address_State']==$query->Address_State) 
            { 

              echo "<option value='".$rows['Address_State_ID']."' selected>".$rows['Address_State']."</option>";                  
            } 
          else 
            { 
              echo "<option value='".$rows['Address_State_ID']."'>".$rows['Address_State']."</option>";                  

            } 
          }  
          ?> 
         </select> 
        </div> 
        <div> 
         <label for="form-field-select-3">City : </label> 
         <br /> 
         <select class="chosen-select form-control" id="City" name="City" data-placeholder="Choose a City..."> 
          <option value="0"> </option> 
          <?php 
          $query=$this->db->query("select city_name from ref_city where city_id='".$property->City."'"); 
          $query=$query->row(); 
          foreach($city_name as $rows) 
          { 
           if($rows['city_name']==$query->city_name) 
            { 

            echo "<option value='".$rows['city_id']."' selected>".$rows['city_name']."</option>";                  
            } 
            else 
            { 
            echo "<option value='".$rows['city_id']."'>".$rows['city_name']."</option>";                  

            } 
          } 
            ?> 

         </select> 
        </div> 
        <div> 
         <label for="form-field-select-3">Locality : </label> 
         <br /> 
         <select class="chosen-select form-control" id="Locality" name="Locality" data-placeholder="Choose a Location..."> 
          <option value="0"> </option> 
           <?php 
          $query=$this->db->query("select locality_name from ref_locality where locality_id='".$property->Locality."'"); 
          $query=$query->row(); 
          foreach($locality_name as $rows) 
          { 
           if($rows['locality_name']==$query->locality_name) 
            { 

            echo "<option value='".$rows['locality_id']."' selected>".$rows['locality_name']."</option>";                  
            } 
            else 
            { 
            echo "<option value='".$rows['locality_id']."'>".$rows['locality_name']."</option>";                  

            } 
          } 
            ?> 
         </select> 
        </div> 
        </div> 
       </div> 
      </div> 
    </div> 

Answer 1

我覺得你想是這樣的

http://www.91weblessons.com/codeigniter-ajax-country-state-city-drop-down/

的javascript：

<script> 
    function selectState(country_id)//on change of country select box 
    { 
     if(country_id!="-1"){ 
     loadData('state',country_id); 
     $("#city_dropdown").html("<option value='-1'>Select city</option>"); 
     }else{ 
     $("#state_dropdown").html("<option value='-1'>Select state</option>"); 
     $("#city_dropdown").html("<option value='-1'>Select city</option>"); 
     } 
    } 

    function selectCity(state_id)//on change of state select box 
    { 
     if(state_id!="-1"){ 
     loadData('city',state_id); 
     }else{ 
     $("#city_dropdown").html("<option value='-1'>Select city</option>"); 
     } 
    } 


    function loadData(loadType,loadId){ 
     var dataString = 'loadType='+ loadType +'&loadId='+ loadId; 
     $("#"+loadType+"_loader").show(); 
     $("#"+loadType+"_loader").fadeIn(400).html('Please wait... <img src="image/loading.gif" />'); 
     $.ajax({ 
     type: "POST", 
     url: "loadData", 
     data: dataString, 
     cache: false, 
     success: function(result){ 
      $("#"+loadType+"_loader").hide(); 
      $("#"+loadType+"_dropdown").html("<option value='-1'>Select "+loadType+"</option>"); 
      $("#"+loadType+"_dropdown").append(result); 
     } 
    }); 
    } 

    </script> 

控制器：

<?php 

    public function index() 
    { 
     $this->load->model('model'); 
     $result['list']=$this->model->getCountry(); 
     $this->load->view('top'); 
     $this->load->view('index',$result); 
     $this->load->view('footer'); 
    } 

    public function loadData() 
    { 
     $loadType=$_POST['loadType']; 
     $loadId=$_POST['loadId']; 

     $this->load->model('model'); 
     $result=$this->model->getData($loadType,$loadId); 
     $HTML=""; 

     if($result->num_rows() > 0){ 
     foreach($result->result() as $list){ 
      $HTML.="<option value='".$list->id."'>".$list->name."</option>"; 
     } 
     } 
     echo $HTML; 
    } 
    ?> 

型號：

<?php 
function getCountry() 
{ 
    $this->db->select('id,country_name'); 
    $this->db->from('country'); 
    $this->db->order_by('country_name', 'asc'); 
    $query=$this->db->get(); 
    return $query; 
} 

function getData($loadType,$loadId) 
{ 
    if($loadType=="state"){ 
    $fieldList='id,state_name as name'; 
    $table='state'; 
    $fieldName='country_id'; 
    $orderByField='state_name'; 
    }else{ 
    $fieldList='id,city_name as name'; 
    $table='city'; 
    $fieldName='state_id'; 
    $orderByField='city_name'; 
    } 
    $this->db->select($fieldList); 
    $this->db->from($table); 
    $this->db->where($fieldName, $loadId); 
    $this->db->order_by($orderByField, 'asc'); 
    $query=$this->db->get(); 
    return $query; 
} 

?>