drupal 7 hook_form_alter

hook_form_alter is a Drupal 7 hook that allows you to alter the form elements and their properties before they are rendered. This hook is commonly used to modify existing forms provided by Drupal or contributed modules to suit specific needs.

To implement hook_form_alter in Drupal 7, follow these steps:

  1. Create a custom module or open an existing one. Make sure the module is enabled.

  2. Define a function in your module using the following naming convention: MODULE_NAME_form_alter(&$form, &$form_state, $form_id). Replace MODULE_NAME with the actual name of your module.

  3. Inside the function, you can modify the $form array to alter the form elements. You can add, remove, or modify form elements and their properties according to your requirements.

  4. The $form_state parameter is used to access and manipulate the form state information. You can use it to store or retrieve values during form submission or validation.

  5. The $form_id parameter contains the unique ID of the form being altered. You can use this to target specific forms if needed.

Here's an example of a basic implementation of hook_form_alter:

function MODULE_NAME_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'my_form_id') {
    // Modify form elements here.
    $form['example_element']['#title'] = t('New Title');
    $form['example_element']['#description'] = t('New description');

In this example, we check if the form ID is 'my_form_id' and then modify the 'example_element' by changing its title and description.

Remember to clear Drupal's cache after implementing or modifying hook_form_alter, as it might be necessary for the changes to take effect.

That's the basic usage of hook_form_alter in Drupal 7. It allows you to customize and extend forms to meet your specific requirements without modifying the original form code.