FreeBASIC JavaScript WebSocket example
======================================

`emscripten-websocket.bas` uses the optional Emscripten WebSocket binding
installed as `emscripten_websocket.bi` with fbc-js.

Build it from this directory with:

    fbc-js -Wl -lwebsocket -x emscripten-websocket.html emscripten-websocket.bas

Start the local host in another terminal:

    node emscripten-websocket-host.js --root .

Then open `http://127.0.0.1:18087/emscripten-websocket.html`. The client uses
`ws://127.0.0.1:18087` by default, sends one message, prints the echoed reply,
and closes the connection. The host serves the generated page and implements a
small WebSocket echo service without npm packages.

To connect somewhere else, change `websocketUrl` in the example. This keeps
the browser build independent of page query-string and host command-line
conventions.

The `-Wl -lwebsocket` pair matters. Emscripten does not link its WebSocket
implementation unless the program requests it. The browser WebSocket API is
asynchronous, so a program must keep yielding to the event loop after it opens
a socket. The example uses `Sleep` for that purpose.

When serving the generated page over HTTPS, use a `wss://` endpoint. Browsers
normally reject an insecure `ws://` connection from a secure page.