AJAX in Drupal Forms?

How would you go about constructing a step by step form that uses AJAX through Drupal to pull the next form ste开发者_StackOverflowp?

For example,

Step 1:
   I like Baseball
   I don't like Baseball.

When that person clicks on either Like or Don't Like, I want to use AJAX to recognize and pull the next part of the form, remove/hide the first section since its not needed, and present the next section.

Example:

Step 1:
   I like Baseball
   *click
(fade out)


Step 2:
   My favorite team is __________
   The player I like most is __________

What is the best way to do this through Drupal Form API? I know how to build the forms and modules, but I have never used AJAX yet. I know a few things exist out there that are supposed to help, but I wanted to know if anyone here has done it and how they approached it.

You may want to give a look at the AHAH helper module.

usually i am create full form with fieldsets, then control them manually by jquery.
i assume there lot of ready to go modules in drupal, some of these:
http://drupal.org/project/conditional_fields / http://drupal.org/project/multistep
also: http://www.google.ru/search?q=drupal+multistep+ajax+form

If you don't want to write any code, and don't need the entered data to be drupal nodes, I suggest using the webform module. It has a pretty simple UI for building forms, and allows you do do multipage forms with conditional fields. You can then export the results as CSV, email them, etc.

I have made to solutions for this problem in drupal 7. First one I solve it with Ajax as was requested(if someone want I can convert this to drupal6), however it should be better to solve this using attribute #states. So also made a solution in the bottom using states.

How to solve this using Ajax:

function ajax_in_drupal_form($form, &$form_state)
{
    $baseball = array(
        'like' => t('I like Baseball'),
        'unlike' => t('I don\'t like Baseball')
    );

    $form['step'] = array(
        '#prefix' => '<div id="baseball-wrapper">',
        '#suffix' => '</div>',
    );

    if ($form_state['values']['baseball'] == 'like') {
        $form['step']['team'] = array(
            '#type' => 'textfield',
            '#title' => t('My favorite team is'),

        );
        $form['step']['player'] = array(
            '#type' => 'textfield',
            '#title' => t('The player I like most is'),
        );
    }
    else if ($form_state['values']['baseball'] == 'unlike') {
        $form['step']['other'] = array(
            '#type' => 'textfield',
            '#title' => t('What do you like'),
        );
    }
    else {
        $form['step']['baseball'] = array(
            '#type'    => 'radios',
            '#options' => $baseball,
            '#title'   => t('Select your option'),
            '#ajax' => array(
                'callback' => 'ajax_update_step_callback',
                'wrapper'  => 'baseball-wrapper',
            ),
        );
    }

    return $form;
}

function ajax_update_step_callback($form, $form_state) {
    return $form['step'];
}

Here is the solution using #states(The preferred way of solving it):

function states_in_drupal_form($form, &$form_state)
{
    $baseball = array(
        'like' => t('I like Baseball'),
        'unlike' => t('I don\'t like Baseball')
    );

    // step 1
    $form['step']['baseball'] = array(
        '#type'    => 'radios',
        '#options' => $baseball,
        '#title'   => t('Select your option'),
        '#states' => array(
            'invisible' => array(':input[name="baseball"]' => array('checked' => TRUE),
            ),
        )

    );

    // step 2 like baseball
    $form['step']['team'] = array(
        '#type' => 'textfield',
        '#title' => t('My favorite team is'),
        '#states' => array(
            'visible' => array(':input[name="baseball"]' => array('checked' => TRUE)),
            'visible' => array(':input[name="baseball"]' => array('value'   => 'like')),
        )
    );
    $form['step']['player'] = array(
        '#type' => 'textfield',
        '#title' => t('The player I like most is'),
        '#states' => array(
            'visible' => array(':input[name="baseball"]' => array('checked' => TRUE)),
            'visible' => array(':input[name="baseball"]' => array('value'   => 'like')),
        )
    );

    // step 2 I don't like baseball
    $form['step']['other'] = array(
        '#type' => 'textfield',
        '#title' => t('What do you like'),
        '#states' => array(
            'visible' => array(':input[name="baseball"]' => array('checked' => TRUE)),
            'visible' => array(':input[name="baseball"]' => array('value'   => 'unlike')),
        )
    );

    return $form;
}