Auto action to a confirmation screen

Is it possible to use a code auto action at onbeforeuserupdate to run a javascript to get user confirmation popup on whether to "proceed" or "cancel".

If it is a "proceed" or cancel what object/hyperlink/url do i call in cb to continue to update?

Thanks in advance..

No, there's no HTML output during a save operation. You would need to bind to the form submit event using jQuery on the profile edit display trigger to intercept the form submit entirely to show your confirm dialog.