AjaxChat is a Scripts software developed by I.S. Lyubinskiy. After our trial and test, the software is proved to be official, secure and free. Here is the official description for AjaxChat:

MarydownEditor: Ajax Chat is a light-weight customizable web chat software implemented in JavaScript and PHP. The script does not require Java, Flash, or any other plugins. Features:
Public and private chat.
Login as a registered user or as a guest.
Away status, custom colors, smileys, user gender/status icons.
Ajax Chat can be integrated with a third-party Membership system by implementing user authentication routine. Advanced integration options: if user is logged in to the website, he can be logged in to the chat automatically.