shime/app.js

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

server.listen(4000);

app.get('/', function(request, response){
  response.sendfile(__dirname + "/index.html");
});

var activeClients = 0;

io.sockets.on('connection', function(socket){clientConnect(socket)});

function clientConnect(socket){
  activeClients +=1;
  io.sockets.emit('message', {clients:activeClients});
  socket.on('disconnect', function(){clientDisconnect()});
}

function clientDisconnect(){
  activeClients -=1;
  io.sockets.emit('message', {clients:activeClients});
}

## index.html
<!DOCTYPE html>
<html>
  <head>
    <title>Connection Counter</title>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
    <script src="/socket.io/socket.io.js"></script>
    <script>
      function msgReceived(msg){
        $clientCounter.html(msg.clients);
      }

      $(document).ready(function () {
        $clientCounter = $("#client_count")

        var socket = io.connect('http://localhost:4000');
        socket.on('message', function(msg){msgReceived(msg)});
      });
    </script>
  </head>
  <body>
    <p><span id="client_count">0</span> connected clients</p>
</body>
</html>
	var express = require('express')
	, app = express()
	, http = require('http')
	, server = http.createServer(app)
	, io = require('socket.io').listen(server);

	server.listen(4000);

	app.get('/', function(request, response){
	response.sendfile(__dirname + "/index.html");
	});

	var activeClients = 0;

	io.sockets.on('connection', function(socket){clientConnect(socket)});

	function clientConnect(socket){
	activeClients +=1;
	io.sockets.emit('message', {clients:activeClients});
	socket.on('disconnect', function(){clientDisconnect()});
	}

	function clientDisconnect(){
	activeClients -=1;
	io.sockets.emit('message', {clients:activeClients});
	}
	<!DOCTYPE html>
	<html>
	<head>
	<title>Connection Counter</title>
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
	<script src="/socket.io/socket.io.js"></script>
	<script>
	function msgReceived(msg){
	$clientCounter.html(msg.clients);
	}

	$(document).ready(function () {
	$clientCounter = $("#client_count")

	var socket = io.connect('http://localhost:4000');
	socket.on('message', function(msg){msgReceived(msg)});
	});
	</script>
	</head>
	<body>
	<p><span id="client_count">0</span> connected clients</p>
	</body>
	</html>