Thanks to a project that has been previously pointed out (node WebRTC bindings - https://github.com/js-platform/node-webrtc) interop between a browser and node applications isn't too far away.

There is this issue which is being worked on at the moment in the node-webrtc library:

https://github.com/js-platform/node-webrtc

Once that's resolved data channel connectivity between a browser and command-line app, server, etc should be reasonably simple. While this bug is outstanding, it is possible to fall back to Rtp data channels in the browser and if that is something that is of interest then we can look at putting together some examples with rtc.io if that would help you out.