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
if(module_exists(‘transliteration’)){
# including Transliteration functions
require_once(drupal_get_path(‘module’, ‘transliteration’) .’/transliteration.inc’);
$css_class = transliteration_clean_filename($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).