I am new to server side JS. I was reading about Socket.io.
Is it possible to run socket.io on js platforms other than node like Mozilla Rhino ?
Sorry! It appears you have to build your own. Node JS took the Google V8 engine and added methods for doing things on the server. Rhino will require the same.
Rhino allows you to access Java Classes, so any server side networking you need just requires a little Java code.
There is a great tutorial on the topic here: http://www.mailsend-online.com/blog/internet-protocols-and-rhino-javascript.html