How can I create WebServer and WebSocket on one port (80)?

It's just as shown here: http://www.espruino.com/ws#websocket-server

Creating a WebSocket server on a port also creates an HTTP server on that same port. You can see that onPageRequest gets called in the example, and that's exactly the same function that'd get called if you did http.createServer(onPageRequest).listen(8080);.

Hope that helps!