Webform popup on load

Hi,
would any of you know how to setup a webform on a popup when a certain page load?

I have a webform setup but I can only make it appear on a block. I would like to have it as a popup that wont be blocked with browser (colorbox would be awesome) for a specific page (the last page of the course for example). It's a simple survey.

I have search but no luck. Thanks all for your help. Drupal 6 or 7.

Edit: Edit: I have this http://drupal.org/node/491428 but it's about clicking on a link, not on loading a page