8.js

/**
 *Simple Express app that demonstrates
 *waiting for server 'listen' event.
 */

//create an express app

var express = require('express'),
	morgan = require('morgan'),
	app = express(),
	port = process.env.PORT || 3000;

// add logging middleware

app.use(morgan('dev'));

// route handler for GET /

app.get('/', function(req, res) {
	var data = '<h1>hello world</h1>';
	res.send(data);
});

//listen on localhost:3000

var server = app.listen(port, function() {
	// the callback is added as a listener for the server's 'listen' event
	// see: http://nodejs.org/api/net.html#net_server_listen_path_callback

	// server is an http.Server, which is a net.Server
	// http://nodejs.org/api/http.html#http_class_http_server
	// http://nodejs.org/api/net.html#net_class_net_server
	// http://nodejs.org/api/net.html#net_server_address

	console.log('server started on port %s', server.address().port);
});