I\'m interested in building a small real-time multiplayer game, using HTML5/JavaScript for the client and probably Java for the server software.
I looked into WebSoc
If you are planing to use JavaScript for your game (as you are) then WebSocket is the best choice for you. And if you want to support older version of Internet Explorer then think of Signal R system Microsoft developed. They are using WebSocket under the hood, but they also have a few fall back options...so protocol will use the best available solution available.
http://signalr.net/