[support] Triggering Form Submit

I used to be able to add the following to a select list to trigger form submission when the selected value was changed. <select ... onChange="this.form.submit(); " This would be executed as javascript and would trigger submission method of the form object that contained the select widget. How can I do the same using the Drupal form definition? I tried "#ahah" but can't seem to get it to work. Any clues? I want to cause the form validation and optionally the post modules to be executed when the selection has change. Warren Vail