1<script src="/socket.io/socket.io.js"></script>
2<script>
3 const socket = io();
4</script>
1const express = require('express');const app = express();const http = require('http');const server = http.createServer(app);const { Server } = require("socket.io");const io = new Server(server);app.get('/', (req, res) => { res.sendFile(__dirname + '/index.html');});io.on('connection', (socket) => { console.log('a user connected');});server.listen(3000, () => { console.log('listening on *:3000');});