Also, check out crossbar.io and the WAMP protocol, offering transparent, clean and yet simple PUB/SUB & RPC accross languages, including C++, Python, PHP and JS (node and yes, browsers).
WAMP is a protocol, Wangle is a framework that you can use to implement protocols (like WAMP), crossbar is a broker (an application that implements the protocol using a [python] framework. So it's not a direct comparison.
