I use his code to populate a select after giving à zipcode.

$form['responsible']['zipcode'] = array(       '#type'               => 'textfield',       '#title'              => t('Zipcode'),       '#default_value'      => empty($account->Dossier->responsable->adresse->codePostal) ? Null : $account->Dossier->responsable->adresse->codePostal,       '#required'           => True,       '#maxlength'          => 5,       '#ajax' => array(         'callback' => 'ajax_get_cities_callback',         'wrapper' => 'edit-city',         'method' => 'replace',       ),     );      $form['responsible']['city'] = array(       '#type'               => 'select',       '#title'              => t('City'),       '#options'            => array(),       '#required'           => True,     ); 

My callback

function ajax_get_cities_callback($form, $form_state){   $client = new SoapClient('myWebservice',array("trace" => true,  "exceptions" => true,));   $requestParams = array(     'parameters' => array (       'numSite' => 1058,       'typeListes' => array(         'RechercheTypeListe' => array(           'typeListe' => 'LST_VILLE',           'param1' => $form_state['values']['zipcode']           )         )     )   );   $dataresponse->requestParams = $requestParams;   $response = "";   try {       $response = $client->__Call('GetListes',$requestParams);   }   catch (Exception $e) {     var_dump($e);     return False;   }    $form['responsible']['city']['#options'] = array(     0 => "aaaa",     1 => "test2",     2 => "test3"   );    return $form['responsible']['city'];  } 

When I give a zipcode, a new select is created behind the first one.( picture here: https://www.uploady.com/#!/download/zjKvglzRTSe/ZIMYkjSAAaLrUFUq) I tried to return only $form[‘responsible’][‘city’][‘#options’] but it does not fixe.

Any idea ?

Thank you