Question

I made a chat using PHP and JavaScript chat and there is a disconnect button which removes user from the chat removing him from user list first. But if the user closes browser then he will remain in the user list. How do I check if he left?

This must be done without putting any handles on page closing in JS because if user kills the browser then he will remain in chat.

By the way , JS script always sends a request to the PHP page which constantly checks for new messages in a loop and when there are some, the script prints them out and exits. Then it repeats all over again.

EDIT : How do I make a heartbeat thing in PHP? If a user closes the page the script execution will be terminated therefore we won’t be able to check if the user is still connected in the same script.

Answer 1

Sorry, there is no reliable way of doing this, that’s the way HTTP was built – it’s a “pull” protocol.
The only solution I can think of is that “valid” and logged in clients must query the server in a very small interval. If they don’t, they’re logged out.