Customising the labels on radio-buttons

This blog post is more than 9 years old, so the content may be out of date.

Thought I'd quickly blog about this whilst this is fresh in my head!

Sometimes you want to add detail to a set of radio-buttons - e.g. you may want to show an example image below the radio-button's label:

Choose cable connection
( ) VGA
    [ pic of VGA cable ]

( ) DVI
    [ pic of DVI cable ]

( ) DisplayPort
    [ pic of DisplayPort cable ]

You would usually start with this Drupal code:

$form['cable_type'] = array(
  '#type' => 'radios',
  '#title' => t('Choose cable connection'),
  '#options' => array('vga' => t('VGA'),
                      'dvi' => t('DVI'),
                      'displayport' => t('DisplayPort'),

The problem is that you can add a #description property to the set of radio-buttons, but not to individual radio buttons.

The solution is to use an after-build handler to inject the description.

 * Implementation of hook_form_alter().
function foo_form_alter(&$form, &$form_state, $form_id) {
  if($form_id == 'xxx_node_form') {
    // Add a custom after-build handler to the cable-type element.
    $form['cable_type']['#after_build'][] = '_foo_after_build';
 * After-build handler to add the example images to the inline/block element.
function _foo_after_build($element, $form_state) {
  foreach(element_children($element['value']) as $key) {
    // Get the image-tag using a custom helper function.
    $desc = _foo_get_img($key);
    $element['value'][$key]['description'] = $desc;
  return $element;

This can be used on normal FAPI elements, and on CCK radio-buttons, as shown by the form-alter above.


I’ve not too long ago started a blog, the knowledge you present on this website has helped me tremendously. Thanks for all your time & work.

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