Does LeapJS still work?
LeapJS no longer works on version 4, but is effective on the 3.2.1 software.
What's the story with LeapJS?
With the version 4 software, we stripped out support for all the legacy APIs. In a C++ application a developer could easily just implement a new wrapper on LeapC (using LeapCxx) and still be able to program in C++. But since JS has to run in a browser, there needs to be some native application passing the Leap Motion data along. Historically the Leap Service has handled this by setting up a WebSocket server through which the hand tracking data is delivered.