var app = require('http').createServer(handler) 
io = require('socket.io').listen(app)  
fs = require('fs') 
app.listen(80) 
function handler (req, res) {  
fs.readFile(__dirname + '/index.html',function (err, data) {
if (err) {res.writeHead(500);   
return res.end('Error loading index.html');
} 
res.writeHead(200);
res.end(data);
});
}
io.sockets.on('connection', function (socket) {  
socket.emit('news', { hello: 'world' });  
socket.on('my other event', function (data) {  
console.log(data);}); });

<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('news', function (data) {  
console.log(data);  
socket.emit('my other event', { my: 'data' });
});
</script>

var app = require('express')()
server = require('http').createServer(app)
io = require('socket.io').listen(server);

server.listen(80);

app.get('/', function (req, res) {
 res.sendfile(__dirname + '/index.html');});

io.sockets.on('connection', function (socket) {
 socket.emit('news', { hello: 'world' });
 socket.on('my other event', function (data) {
  console.log(data);
 });});

// note, io.listen(<port>) will create a http server for youvar io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) {
 io.sockets.emit('this', { will: 'be received by everyone'});

 socket.on('private message', function (from, msg) {
  console.log('I received a private message by ', from, ' saying ', msg);
 });

 socket.on('disconnect', function () {
  io.sockets.emit('user disconnected');
 });});

var io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) {
 socket.on('set nickname', function (name) {
  socket.set('nickname', name, function () {
   socket.emit('ready');
  });
 });

 socket.on('msg', function () {
  socket.get('nickname', function (err, name) {
   console.log('Chat message by ', name);
  });
 });});

var io = require('socket.io').listen(80);var chat = io
 .of('/chat')
 .on('connection', function (socket) {
  socket.emit('a message', {
    that: 'only'
   , '/chat': 'will get'
  });
  chat.emit('a message', {
    everyone: 'in'
   , '/chat': 'will get'
  });
 });

<script>
 var chat = io.connect('http://localhost/chat')
  , news = io.connect('http://localhost/news');
 
 chat.on('connect', function () {
  chat.emit('hi!');
 });
 
 news.on('news', function () {
  news.emit('woot');
 });</script>

var io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) {
 socket.on('ferret', function (name, fn) {
  fn('woot');
 });});
client.html
<script>
 var socket = io.connect(); // TIP: .connect with no args does auto-discovery
 socket.on('connect', function () { // TIP: you can avoid listening on `connect` and listen on events directly too!
  socket.emit('ferret', 'tobi', function (data) {
   console.log(data); // data will be 'woot'
  });
 });</script>

var io = require('socket.io').listen(80);

io.sockets.on('connection', function (socket) {
socket.broadcast.emit('user connected');});

<script src="/socket.io/socket.io.js"></script><script>
 var socket = io.connect('http://localhost');
  
  socket.on("notice", function(data){
    var msg = document.getElementById('all').value;
    document.getElementById('all').innerText = msg + "\n" + data.message;
  });

  var chat_fn = function(){
    var msg = document.getElementById("message").value;
    socket.emit("chat", {message: msg});
  };


  socket.on("nickname ready", function(data){
    alert("nickname changed.");
  });

  var change_nickname = function(){
    var nickname = document.getElementById("nickname").value;
    socket.emit('set nickname', nickname);
  };</script><textarea id="all" cols=40 rows=20></textarea><br /><label>Message:</label><input id="message" type="text" name="message" cols=120/><input id="chat_btn" type="button" value="chat" onclick="javascript:chat_fn()" /><label>NickName:</label><input id="nickname" typee="text" name="nickname" /><input id="chang_name" type="button" value="nickname" onclick="javascript:change_nickname()" />
app.js

var app = require('http').createServer(handler)
 , io = require('socket.io').listen(app)
 , fs = require('fs');


app.listen(80);function handler (req, res) {
 fs.readFile(__dirname + '/index.html',
 function (err, data) {
  if (err) {
   res.writeHead(500);
   return res.end('Error loading index.html');
  }

  res.writeHead(200);
  res.end(data);
 });}

io.sockets.on('connection', function (socket) {
 // socket.emit('news', { hello: 'world' });
 // socket.on('my other event', function (data) {
 //  console.log(data);
 // });

 socket.set('nickname', 'nickname', function(){
 });

 socket.on('set nickname', function(name){
  socket.set('nickname', name, function(){
   console.log("change nickname=>" + name);
   socket.emit('nickname ready');
  });
 });

 socket.on('chat', function(data){
  socket.get('nickname', function(err, name){

  socket.emit("notice", {message: name + ":" + data.message});
  socket.broadcast.emit("notice", {message: name + ":" + data.message});
  console.log("chat: " + data.message);
  });
 });});