socket.io and socket.io-client code example
Example 1: socket..io
<script src="https://cdn.socket.io/socket.io-3.0.1.min.js"></script>
Example 2: socket.io documentation
const socket = new WebSocket('ws://localhost:3000');socket.onopen(() => { socket.send('Hello!');});socket.onmessage(data => { console.log(data);});