Add CSS class to <form> element using webform and template file

Question

I have an existing webform in Drupal 7 which I am trying to theme. So far I managed to add CSS classes, placeholders, prefix, suffix,.. to form elements (fields) but not to the actual <form>-tag?

I tried this:

$form['#attributes']['class'][] = 'form-horizontal';`

But that didn't change anything to the output.

edit: I have found that putting var_dump($form['#attributes']); displays the array below the form-tag. Does that mean that you cannot alter the root element inside a template file (webform-form-8.tpl.php) and that I should implement the hook in template.php?

Answer 1

I believe your edit is correct. You should add the class in a preprocessor function within template.php.

A similar question and answer can be found here.

Answer 2

function THEME_form_alter(&$form, &$form_state, $form_id) {
    $form['#attributes']['class'][] = 'my_class';
}

in a template.php