example for socket.io issue `Double connections with blocking `alert` or `prompt` during io.connect()`

test.html

<script src="http://localhost/socket.io/socket.io.js"></script>
<script>
    var socket = new io.Socket('localhost');
    socket.connect();
    socket.on('connect', function(){

      alert("connected");

    })
    socket.on('message', function(){ })
    socket.on('disconnect', function(){ })
</script>

<script>
  prompt("wait for a few seconds before clicking ok");
</script>

test.js

var http = require('http'), 
        io = require('socket.io'),
        fs = require('fs'),
server = http.createServer(function(req, res){
    // your normal server code
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end(fs.readFileSync('test.html'));
});

server.listen(80);

// socket.io, I choose you
var socket = io.listen(server);

socket.on('connection', function(client){
  console.log("Client connected!");
  client.on('message', function(){});
  client.on('disconnect', function(){});
});