this is for the first time i`m creating a browser based game on my own ,without other students. but how do you create browsergame battlesystem?
my teachers don`t know coz they only have experience with RPG`s
That all depends on the type of RPG you're making. Let's assume it's a turn-based one. In that case, I'd say that to make it look as professional as possible, you'll definitely want to use AJAX. That's a programming method used to reload pages on the fly.
Now, as for how you're to accomplish such a thing you will need to have a core PHP script that handles responses from the browser (sent via AJAX as post data) and generates output that Javascript can then use to perform the appropriate action, for example, replacing the player "standing" image with the player "attacking" image and reducing the opponent's HP by a certain amount. This is all done in javascript with variables.
Heck, come to think of it it might be easier just to do it all in javascript, and just use AJAX to send PHP messages like "okay, the potion has been used, please take it out of the player's inventory".
i`m making one for a browsergame like travian or tribalwars