If it is based on a PHP server (good luck with that btw), I guess you need to handle AJAX calls
You can check out the How do I FAQ
for usage examples interacting with PHP scripts as well.
You may also try the multiplayer plugin
, and then only save the results of the game to the PHP server/database.
This is a different beast though.
As for the turn base gameplay, I had made a tutorial for a local turn based board game
, I guess it needs a bit of modifications to be applied to an online multiplayer game but some of the logic may still apply.
As you say, it's pretty much the same as on local, except you will be awaiting the transition signals from online.