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

Question

Here I am listing all cars.customers want to compare car so they will select from this drop down. A person can select multiple cars. At the first time he is selecting 'Audi' and Saab' I will store it into data base next if he came I need to populate Saab and audi as select how I can do this 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 is my code
<select id="cars" class="multiselect" multiple="multiple" name="cars[]">
<?PHP
if($carslist->num_rows() >0)
{
foreach($carslist->result_array() as $entry):
?> <option value="<?php echo($entry['ID']); ?>" ><?php echo($entry['car_name']); ?></option>
<?php
endforeach;
}
?>
</select>
Following code I tried $resources contain select cars
<select id="cars" class="multiselect" multiple="multiple" name="cars[]">
<?PHP
if($carslist->num_rows() >0)
{
foreach($carslist->result_array() as $entry):
if($resources->num_rows() >0)
{
foreach($resources->result_array() as $car):
if($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 it showing error

Answer 1

Here, try something like this, and see if it works:
Here is the 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 this is the view:
<select id="cars" class="multiselect" multiple="multiple" name="cars[]">
<option value="">Select:</option>
<?php
foreach( $cars as $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>