This a Free AJAX script to add comments in the website, uses PHP, MySQL, and JavaScript (with jQuery). The script paginate the comments, without affecting the rest of the page content, or page URL, and it can be included in both HTML, and PHP files (but the server must have installed PHP). The script can be used with multiple pages of a site, whatever the type of the page URL (modified or not with mod-rewrite). Can be set to allow only logged users to add comments, and has many other settings, and Admin management. Just test it.