Note that this is currently maintained in the Examples project so the code here may not be the latest.
In this example, we just use checkboxes to determine whether textboxes are displayed.
One of the fundamental ideas of having a form change based on selections within the form is that the form is reconfiguring itself based on $form_state. So here, the generation of the form is driven by $form_state['values']. If the checkbox for last name is checked, then we generate a textfield for last name.
Update 2009-08-23: I note that checkboxes and radios do not actually work correctly in Internet Explorer.
(Experiment with this one at http://d6.drupalexamples.info/examples/ahah_example/autotextfields.)
/**
* @file
* Show/hide textfields based on checkbox clicks
*/
function ahah_demo_autotextfields(&$form_state) {
$form['ask_first_name'] = array(
'#type' => 'checkbox',
'#title' => t('Ask me my first name'),
'#default_value' => $form_state['values']['ask_first_name'],
'#ahah' => array(
'path' => 'ahah_demo/autotextfields/callback',
'wrapper' => 'textfields',
'effect' => 'fade',
)
);
$form['ask_last_name'] = array(
'#type' => 'checkbox',
'#title' => t('Ask me my last name'),
'#default_value' => $form_state['values']['ask_last_name'],
'#ahah' => array(
'path' => 'ahah_demo/autotextfields/callback',
'wrapper' => 'textfields',
'effect' => 'fade',
),
);
$form['textfields'] = array(
'#title' => t("Generated text fields for first and last name"),
'#prefix' => '
',
'#suffix' => '
',
'#type' => 'fieldset',
'#description' => t('This is where we put automatically generated textfields'),
);
if ($form_state['values']['ask_first_name']) {
$form['textfields']['first_name'] = array(
'#type' => 'textfield',
'#title' => t('First Name'),
);
}
if ($form_state['values']['ask_last_name']) {
$form['textfields']['last_name'] = array(
'#type' => 'textfield',
'#title' => t('Last Name'),
);
}
$form['submit'] = array(
'#type' => 'submit',
'#value' => t('Click Me'),
);
return $form;
}
function ahah_demo_autotextfields_callback() {
$form_state = array('storage' => NULL, 'submitted' => FALSE);
$form_build_id = $_POST['form_build_id'];
$form = form_get_cache($form_build_id, $form_state);
$args = $form['#parameters'];
$form_id = array_shift($args);
$form_state['post'] = $form['#post'] = $_POST;
$form['#programmed'] = $form['#redirect'] = FALSE;
drupal_process_form($form_id, $form, $form_state);
$form = drupal_rebuild_form($form_id, $form_state, $args, $form_build_id);
$textfields = $form['textfields'];
$output = drupal_render($textfields);
// Final rendering callback.
print drupal_json(array('status' => TRUE, 'data' => $output));
exit();
}
?>
