Guestbook v1: Post and display comments in a guestbook

This class can be used to post and display comments in a guestbook.

It can generate the pages that display comment submission forms and the posted comments.

When a comment is posted the comment message and the author contact information is stored in a MySQL database table.

The comment author also receive a verification message in the e-mail address that they specify.

The message contains a special URL with a code that points to a page that the comment author needs to access to verify the address is authentic. The comment is only published when the author's e-mail address is verified.