This is a sample project that demonstrates a connection between javascript running in the browser, and python running in the backend. You can send messages back and forth between the frontend and the backend over websockets, using SocketIO.
You will need python3 in order to run this code.
pip install -r requirements.txt
python app.py
Open up your browser at localhost:5000 and try sending messages between your browser and python. Any keyboard presses you make in the python app will be sent to the frontend.