I have a webform created using interface, and need to hide some fields through button. Using form_alter I have added that button added AJAX call with it. Now I want to remove/hide certain element using that button and AJAX.

Below is the sample code

function xyz_user_signup_form_webform_submission_form1_form_alter(array &$form, FormStateInterface $form_state, $form_id) {

  $form['#attached']['library'][] = 'xyz/xyz.global';

  $form['start'] = [
      '#type' => 'button',

      '#ajax' => [
        'callback' => 'xyz_user_signup',
      '#value' => t('START >>'),


function xyz_user_signup(array &$form, FormStateInterface $form_state) {

    $elements = &WebformFormHelper::flattenElements($form['elements']);

    $elements['field1']['#access'] = FALSE;

    return $elements;

On clicking start button I want to hide field1.

  • Please share your inputs how about sharing your alter code... otherwise we would have to be psychics.
    – No Sssweat
    Oct 31, 2019 at 8:21
  • Sure let me edit the issue
    – parth.k
    Oct 31, 2019 at 8:22

1 Answer 1


Your AJAX needs to have a target ID where it will put your AJAX output. You declare that ID in the wrapper key.

In your form_alter

  '#ajax' => [
    'callback' => 'xyz_user_signup',
    'wrapper' => 'load-me-here-id', // This element is updated with this AJAX callback.

Then you need to wrap the field with this ID so AJAX replaces it.

 $form['elements']['field1']['#attributes'] = ['id' => 'load-me-here-id'];

In your ajax callback

return $elements['field1']; // so it doesn't return the entire form.
  • I implement as per your suggestion, but in ajax callback my code is to set #access property to FALSE of a fieldset element which is not working yet.
    – parth.k
    Oct 31, 2019 at 10:04
  • @parth.k Make sure your ajax is indeed working. For testing purposes, put return 'Hello World'; you should see that "hello world", if not then AJAX it is still not working like it's suppose to.
    – No Sssweat
    Oct 31, 2019 at 11:15
  • @parth.k updated my answer, forgot to add elements to the attributes array.
    – No Sssweat
    Oct 31, 2019 at 11:29

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