var http = require('http');

var server = http.createServer();

server.on('request', function (req, res) {

    res.end('Hello World')

})

server.listen(3000, function () {

    console.log('server is running...')

})

var http = require('http');

http.createServer(function (req, res) {

    res.end('Hello World')

}).listen(3000, function () {

    console.log('server is running...')

})