adding a captcha to a message box in drupal

I have added a message box to a drupal site.I got that massage box from this http://mootools.net/forge/p/message_class url. it is a mootools message bo开发者_运维问答x.I want to add a captcha to the end of the message box.I have installed captcha module to this site.I am using drupal 6.how I can add a captcha to this message box?

Go the admin page, you should have a Captcha section where you should be able to add the ID of the form you want to add the Captcha too. Typically you find this ID number in the form URL, when you edit it.