Same name and namespace in other branches
  1. 10 core/lib/Drupal/Core/Form/form.api.php \hook_form_FORM_ID_alter()
  2. 7.x modules/system/system.api.php \hook_form_FORM_ID_alter()
  3. 8.9.x core/lib/Drupal/Core/Form/form.api.php \hook_form_FORM_ID_alter()
  4. 9 core/lib/Drupal/Core/Form/form.api.php \hook_form_FORM_ID_alter()

Provide a form-specific alteration instead of the global hook_form_alter().

Modules can implement hook_form_FORM_ID_alter() to modify a specific form, rather than implementing hook_form_alter() and checking the form ID, or using long switch statements to alter multiple forms.

Note that this hook fires before hook_form_alter(). Therefore all implementations of hook_form_FORM_ID_alter() will run before all implementations of hook_form_alter(), regardless of the module order.

Parameters

$form: Nested array of form elements that comprise the form. The arguments that drupal_get_form() was originally called with are available in the array $form['#parameters'].

$form_state: A keyed array containing the current state of the form.

See also

hook_form_alter()

drupal_prepare_form()

Related topics

1 function implements hook_form_FORM_ID_alter()

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

book_form_node_delete_confirm_alter in modules/book/book.module
Form altering function for the confirm form for a single node deletion.

File

developer/hooks/core.php, line 803
These are the hooks that are invoked by the Drupal core.

Code

function hook_form_FORM_ID_alter(&$form, &$form_state) {

  // Modification for the form with the given form ID goes here. For example, if
  // FORM_ID is "user_register" this code would run only on the user
  // registration form.
  // Add a checkbox to registration form about agreeing to terms of use.
  $form['terms_of_use'] = array(
    '#type' => 'checkbox',
    '#title' => t("I agree with the website's terms and conditions."),
    '#required' => TRUE,
  );
}