text browser game

I'm pretty noobish at web coding / webdev.  I'm trying to figure out how I could write a browser game using only JavaScript on the client-side (ie. no browser plug-ins).  But I'm stuck on figuring out how to handle everything server-side.

The only thing I've thought of is to store everything in a SQL database, and just have the AJAX post some information to a PHP file that will take care of everything.  However, I'm wondering if there are other, better ways of doing this that I can't think of.  I'm also not sure about handling concurrent players because I haven't done very much with databases before, so I'm not sure whether I'll have to worry about race conditions or something.

Any ideas or advice would be appreciated.

>>7
Oh, I see.
If you want real-time, AJAX still won't do that (you will have to poll at intervals); if you want true-ish realtime, look into server push stuff, especially the Web Sockets API which will be part of HTML5.
Input will be trivial, perhaps an input box that submits to a script that returns 204 or with an onSubmit that does some shit or something.