To test this out, open a terminal window and write:
npm install mqtt -g
Navigate to the example directory and write:
npm install
Start the server:
sudo npm start
It needs sudo to listen on port 80.
You can now try sending a message to the broker the example is connected to:
mqtt pub -t 'hello/world' -h 'test.mosquitto.org' -m 'Hola'
Note this is an echo server.
Open a web browser, navigate to http://localhost and open the console.
Try sending messages from terminal as we did before:
mqtt pub -t 'hello/world' -h 'test.mosquitto.org' -m 'Hola'
You should now see messages being logged on your browser console.
If you want to send messages from client to broker, try clicking the button that says "Say Hello". Have a look at your terminal after clicking.
Feel free to play around.