Modifying Forms Using Alter Hooks

The ability of themes to use alter hooks is new in Drupal 7.

Using an alter hook is perfect for quick changes like:

-Simple changes to form labels, descriptions, and other properties.
-Changing the order in which the form elements print using the #weight property.
-Wrapping a few elements in a <div> or <fieldset>.
-Hiding or removing form elements that are not required.
-Adding some markup to a form.

1. hook_form_alter(): Runs for all forms.
2. hook_form_FORM_ID_alter(): Runs for a specific form ID.

Implementation of hook_form_alter() to target all or multiple forms

Code:Implementation of hook_form_alter() to target all or multiple forms

Code:Implementation of hook_form_FORM_ID_alter() to target a specific form

CODE:. Implementation of hook_form_FORM_ID_alter() to target a specific form

• <?php
• /**
•  * Implements hook_form_FORM_ID_alter().
•  */
• function mytheme_form_contact_site_form_alter(&$form, &$form_state) {
• // Add a #markup element containing your note and make it display at the top.
• $form[‘note’][‘#markup’] = t(“We’d love hear from you. Expect to hear back from us in 1-2 business days.”);
• $form[‘note’][‘#weight’] = -1;
• // Change labels for the ‘mail’ and ‘name’ elements.
• $form[‘name’][‘#title’] = t(‘Name’);
• $form[‘mail’][‘#title’] = t(‘E-mail’);
• // Hide the subject field and give it a standard subject for value.
• $form[‘subject’][‘#type’] = ‘hidden’;
• $form

hook_form_alter

Example:

<?php>

/* implements hook_form_alter().  */

function demo_form_alter(&$form_state, $form_id ) {

 #krumo($form_id);          /* this will help you find the dir  , using # disable the location mapping*/

switch ( $form_id) {

case ‘user_profile_form’ :

$form[ ‘account’ ] [‘pass’] [#description’] = t (‘ To change the password here . . .  txt messages edit here . . ‘)

krumo($form);

break;

}

}

krumo(alert)

use the version7 :hook_form_alter(&$form, &$form_state, $form_id)

Parameters

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

$form_state: A keyed array containing the current state of the form. The arguments thatdrupal_get_form() was originally called with are available in the array $form_state[‘build_info’][‘args’].

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

Testing Example Code:
*/

<?php
/**
* Implements hook_form_FORM_ID_alter().
*/
function mytheme_form_contact_site_form_alter(&$form, &$form_state) {
// Add a #markup element containing your note and make it display at the top.

// Change labels for the ‘mail’ and ‘name’ elements.
$label[‘Arrival Date’][‘#title’] = t(‘Date Plan’);
$form[‘form-required’][‘#title’] = t(‘Date End’);

}

source: api.drupal.org

http://themery.com/dgd7/advanced-theming/forms/with-alter-hooks