Hands-on: Build a Node.js-powered chatroom web app | Part 1: Introduction to Node.js

server.js

var http = require('http');
var port = process.env.port || 1337;
http.createServer(function (req, res) {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('Hello World\n');
}).listen(port);