codeigniter - How do I Populate Multi Select drop dwon using php -

here listing cars.customers want compare car select drop down. person can select multiple cars. @ first time selecting 'audi' , saab' store data base next if came need populate saab , audi select how can using php

<select name="cars" multiple>     <option value="volvo">volvo</option>     <option value="saab">saab</option>     <option value="opel">opel</option>     <option value="audi">audi</option>  </select> 

here code

<select  id="cars" class="multiselect" multiple="multiple" name="cars[]">     <?php           if($carslist->num_rows() >0)         {              foreach($carslist->result_array() $entry):                  ?> <option value="<?php echo($entry['id']); ?>" ><?php echo($entry['car_name']); ?></option>                <?php                 endforeach;         }           ?>     </select> 

following code tried $resources contain select cars

<select  id="cars" class="multiselect" multiple="multiple" name="cars[]">     <?php           if($carslist->num_rows() >0)         {              foreach($carslist->result_array() $entry):                    if($resources->num_rows() >0)                  {                        foreach($resources->result_array() $car):                          if($entry['id'] == $employee['car_id'])                         {                            $select = 'selected="selected"';                                              }                        else                         {                            $select = '';                                                 }                      endforeach;                      }                                       ?> <option value="<?php echo($entry['id']); ?>" <?php echo $select;?>  ><?php echo($entry['car_name']); ?></option>                <?php                 endforeach;         } ?>       </select> 

but showing error

here, try this, , see if works:

here controller:

<?php     function something(){         $data               = array();         $data['cars']       = $this->some_model->some_function_to_return_cars_array();         $data['selected']   = $some_array_of_selected_cars();         $this->load->view('some_view', $data);     } ?> 

and view:

<select  id="cars" class="multiselect" multiple="multiple" name="cars[]">     <option value="">select:</option>     <?php         foreach( $cars $key => $val ){     ?>         <option value="<?php echo $val['some_id'] ?>"          <?php             if( in_array( $val['some_id'], $selected ) ) echo ' selected';         ?>          ><?php echo $val['some_name'] ?></option>     <?php         }     ?> </select>