8.2.x form.api.php hook_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id)
8.0.x form.api.php hook_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id)
8.1.x form.api.php hook_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id)
4.7.x core.php hook_form_alter($form_id, &$form)
5.x core.php hook_form_alter($form_id, &$form)
6.x core.php hook_form_alter(&$form, &$form_state, $form_id)
7.x system.api.php hook_form_alter(&$form, &$form_state, $form_id)

Perform alterations before a form is rendered.

One popular use of this hook is to add form elements to the node form. When altering a node form, the node object retrieved at from $form['#node'].

Parameters

$form_id: String representing the name of the form itself. Typically this is the name of the function that generated the form.

$form: Nested array of form elements that comprise the form.

Return value

None.

Related topics

11 functions implement hook_form_alter()

Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

color_form_alter in modules/color/color.module
Implementation of hook_form_alter().
comment_form_alter in modules/comment/comment.module
forum_form_alter in modules/forum/forum.module
Implementation of hook_form_alter().
menu_form_alter in modules/menu/menu.module
Implementation of hook_form_alter(). Add menu item fields to the node form.
multipage_form_example_form_alter in developer/examples/multipage_form_example.module
Implementation of hook_form_alter(). Here, we set up the 'page' field, which keeps track of what stage the form is in.

... See full list

2 invocations of hook_form_alter()
drupal_prepare_form in includes/form.inc
Prepares a structured form array by adding required elements, executing any hook_form_alter functions, and optionally inserting a validation token to prevent tampering.
upload_js in modules/upload/upload.module
Menu-callback for JavaScript-based uploads.

File

developer/hooks/core.php, line 438
These are the hooks that are invoked by the Drupal core.

Code

function hook_form_alter($form_id, &$form) {
  if (isset($form['type']) && $form['type']['#value'] . '_node_settings' == $form_id) {
    $form['workflow']['upload_' . $form['type']['#value']] = array(
      '#type' => 'radios',
      '#title' => t('Attachments'),
      '#default_value' => variable_get('upload_' . $form['type']['#value'], 1),
      '#options' => array(t('Disabled'), t('Enabled')),
    );
  }
}