Refreshing a dropdown list when selecting another dropdown list.

[eluser]doob[/eluser]
Maybe this can help you.

View 1

Code:

<select name="state" id="selectstate">
    <option value="1">State 1</option>
    <option value="2">State 2</option>
    <option value="3">State 3</option>
    <option value="4">State 4</option>
</select>

<div id="citieswrapper">
<select name="city" id="selectcity">
    <option value="">- Select state</option>
</select>
</div>

jQuery

Code:

$("#selectstate").bind("change",function(){

    $("#citieswrapper").load("/ajax/get_city", {state_id: $(this).val()} );
});

Controller

Code:

<?php

class Ajax extends Controller {

    function Ajax()
    {
        parent::Controller();
        
        $data = array();
    }
    
    function index()
    {
        
    }

    function get_city()
    {
        // Load location model
        $this->load->model('location_model', 'location');

        // Which state to load?    
        $state_id = $this->input->post('state_id');
        
        $data['cities'] = $this->location->get_cities_in_state($state_id)->result();
        
        $this->load->view('ajax/city_list', $data);
    }

}

Model

Code:

<?php

class Location_Model extends Model
{
    function Location_Model()
    {
        parent::Model();
        
        $this->_city_table = "cities";
    }

    function get_cities_in_state($state_id)
    {
        $this->db->where('state_id', $state_id);
        $this->db->order_by('city_name');
        return $this->db->get($this->_city_table);
    }

View: ajax/city_list.php

Code:

<select name="city">
    &lt;?php foreach($cities as $city) : ?&gt;
        <option value="&lt;?php echo $city->city_id; ?&gt;">&lt;?php echo $city->city_name; ?&gt;</option>
    &lt;?php endforeach; ?&gt;
</select>

DB-table: cities

Code:

id        state_id        city_name
1        1                City 1
2        1                City 2
3        2                A city in state 2
4        3                Another city in state 2
5        4                City in state 4
6        4                City two in state 4