The environment: Mac OS + XAMPP server + Chrome. Before running the project, please check the permissions of (chat_msg.json, chat_user.json and uploads) allow read and write. please see the live demo from https://phpchatroomdemo.herokuapp.com/ Here is the structure of this project. Client Side: index.html ----- 1. main page. 2. login/logout 3. keep update chats with update.php online_user.html ----- to show the online user list. Database: chat_msg.json ----- to store the chats records, each of the chat have 3 value. ( username , color , msg ) chat_user.json ----- to store the users records, each of the user have 3 value. ( username (index) , last_login , icon_url) Server: update.php ----- 1. get latest msg. 2. update last_login of user. 3. get online user login.php ----- to push new user data to chat_user.json send_msg.php ----- to push new msg data to chat_msg.json The project is build by lotusfa.