<div class="form-group">
                        <label>supervisor <?php 
echo tpl_students::students();
?>
 : </label>
                        <select name="<?php 
echo tpl_students::students() . '_' . tpl_students::id_supervisor() . '_update';
?>
"
                                id="<?php 
echo tpl_students::students() . '_' . tpl_students::id_supervisor() . '_update';
?>
"
                                class="form-control">
                            <?php 
$new = new students_lib_ad();
echo $new->find_supervisor();
?>
                        </select>
                    </div>


                    <button type="submit" class="btn btn-success" id="update" name="update">Save</button>
                </form>
                </br>
                </br>
                <div class="" id="result_massages_update"></div>
            </div>
        </div>
    </div>
</div>
 public function update_password()
 {
     $lib = new students_lib_ad();
     $lib->update_password();
 }