retrieve id from dropdown/select box codeigniter

Question

Im trying to figure how to retrieve the ID number from a selected value in a dropbox, displaying a list of projects from a table.

At this point what i did was retrieve the value and then search it and get the ID number for that value in the table. Well the field name_project it's "unique" so it's not so bad but i want to retrive the id directly without querying the database offcourse! It's really necessary the use of jquery or javascript to do that?

<?php echo form_open('solucao/inserir',array('class' => 'form-horizontal')); ?>
 <select class="form-control" id="project" name="project">
                            <option>--Choose Project--</option>
                            <?php foreach($projects as $data):?> 
                            <option><?php echo $data->name_project?></option>
                            <?php endforeach;?>  
                            </select>
<?php form_close(); ?>

Note: $data is an array wich contains the ID number!

Thank you!

Answer 1

Hope you have project_id and project_name as field names in your project table

In model:

function getProjectArr()
{
    $res =  $this->db->get("project");
    $ret_arr = array();
    if($res-<num_rows()>0)
    {
       foreach($res->result() as $r)
       {
          $ret_arr[$r->project_id] = $r->project_name;
       }
    } 
    return $ret_arr;
}

In your controller,

$data["project_list"] = $this->MODEL_NAME->getProjectArr();

In View file

echo form_dropdown("project",$project_list,'','id="project" class="form-control"');

You will get dropdown with ids as option value and names as option text.

Answer 2

When you will get the id on select or options tag.

Then get the id of selected option you can use something like this.

document.getElementById('project').addEventListener('change', selectId);
function selectId(){
    alert(this.options[this.selectedIndex].id);
}

Demo

OR

Get the id of select tag then you can use

document.getElementById('project').addEventListener('change', selectId);
function selectId(){
    alert(this.id);
}

Demo2