Add CSS class to drupal form fieldset

Tested on:

  • Drupal 5.x
  • Zen custom subtheme

Customizing Drupal form appearance may sound difficult. But to add a CSS class is (surprisingly!) simple using theme_fieldset themeable function.

  • Copy theme_fieldset code from Drupal manual page
  • Paste to your template.php:
    • If you’re using a Zen theme, change theme_fieldset to zen_fieldset. You can try to use this method with your theme prefix.
    • If you’re using a theme based on phptemplate engine, you can change theme_fieldset to zen_fieldset to have the same effect of above (try one of this, not both).
  • Change the resultant code as you wish.

I’ve attached an example to generate CSS class from fieldset title: Add CSS class to drupal form fieldset.

# custom fieldset CSS class from element #title
$css_class = “my-custom-class-“;
$css_class .= str_replace(” “,”-“,strtolower($element[‘#title’]));
# using transliteration module to transliterate/strip non-ASCII character where available
# including Transliteration functions
require_once(drupal_get_path(‘module’, ‘transliteration’) .’/’);
$css_class = transliteration_clean_filename($css_class);

Adding this code to your template:

  • Take all Drupal generated fieldset title
    • e.g. “Impostazioni del menù”
  • Transform it in a CSS class using Transliteration module
    • e.g. “my-custom-class-impostazioni-del-menu”
  • Queue it with other CSS classes (where available)
    • e.g “collapsible my-custom-class-impostazioni-del-menu”

I apply a previous substitution of whitespace using “-” (transliteration module use underscore “_”) and you can do the same, but later remember to use transliteration_clean_filename to safely sanitize class name for any other case you’ve not contemplated (accents, special characters).