Is there an alternative of ajax that does not require polling without server side modifications?

Question

I\'m trying to create a small and basic \"ajax\" based multiplayer game. Coordinates of objects are being given by a PHP \"handler\". This handler.php file is being polled e

Answer 1

As Ajax only offers you a client server request model (normally termed pull, rather than push), the only way to get data from the server is via requests. However a common technique to get around this is for the server to only respond when it has new data. So the client makes a request, the server hangs on to that request until something happens and then replies. This gets around the need for frequent polling even when the data hasn't changed as you only need the client send a new request after it gets a response.

Since you are using PHP, one simple method might be to have the PHP code call the sleep command for 200ms at a time between checks for data changes and then return the data to the client when it does change.

EDIT: I would also recommend having a timeout on the request. So if nothing happens for say 2 seconds, a "no change" message is sent back. That way the client knows the server is still alive and processing its request.