Engine.IO client `xhr.status = 0` issue

client.js

(function () {
  var socket = new eio.Socket({
    rememberUpgrade: false,
    transports: ['polling']
  });

  socket.on('open', function () {
    console.log('open');
    socket.on('message', function (data) {
      console.log(data);
    });
  });
  socket.on('close', function () {
    console.log('close');
  });
  socket.on('error', function (err) {
    console.log(err);
  });  
})();

engine.io.js

!function(e){if("object"==typeof exports)module.exports=e();else if("function"==typeof define&&define.amd)define(e);else{var f;"undefined"!=typeof window?f=window:"undefined"!=typeof global?f=global:"undefined"!=typeof self&&(f=self),f.eio=e()}}(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);throw new Error("Cannot find module '"+o+"'")}var f=n[o]={exports:{}};t[o][0].call(f.exports,function(e){var n=t[o][1][e];return s(n?n:e)},f,f.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(_dereq_,module,exports){

module.exports =  _dereq_('./lib/');

},{"./lib/":3}],2:[function(_dereq_,module,exports){

/**
 * Module dependencies.
 */

var Emitter = _dereq_('emitter');

/**
 * Module exports.
 */

module.exports = Emitter;

/**
 * Compatibility with `WebSocket#addEventListener`.
 *
 * @api public
 */

Emitter.prototype.addEventListener = Emitter.prototype.on;

/**
 * Compatibility with `WebSocket#removeEventListener`.
 *
 * @api public
 */

Emitter.prototype.removeEventListener = Emitter.prototype.off;

/**
 * Node-compatible `EventEmitter#removeListener`
 *
 * @api public
 */

Emitter.prototype.removeListener = Emitter.prototype.off;

},{"emitter":16}],3:[function(_dereq_,module,exports){

module.exports = _dereq_('./socket');

/**
 * Exports parser
 *
 * @api public
 *
 */
module.exports.parser = _dereq_('engine.io-parser');

},{"./socket":4,"engine.io-parser":17}],4:[function(_dereq_,module,exports){
(function (global){
/**
 * Module dependencies.
 */

var util = _dereq_('./util');
var transports = _dereq_('./transports');
var Emitter = _dereq_('./emitter');
var debug = _dereq_('debug')('engine.io-client:socket');
var index = _dereq_('indexof');
var parser = _dereq_('engine.io-parser');
var parseuri = _dereq_('parseuri');
var parsejson = _dereq_('parsejson');

/**
 * Module exports.
 */

module.exports = Socket;

/**
 * Noop function.
 *
 * @api private
 */

function noop(){}

/**
 * Socket constructor.
 *
 * @param {String|Object} uri or options
 * @param {Object} options
 * @api public
 */

function Socket(uri, opts){
  if (!(this instanceof Socket)) return new Socket(uri, opts);

  opts = opts || {};

  if (uri && 'object' == typeof uri) {
    opts = uri;
    uri = null;
  }

  if (uri) {
    uri = parseuri(uri);
    opts.host = uri.host;
    opts.secure = uri.protocol == 'https' || uri.protocol == 'wss';
    opts.port = uri.port;
    if (uri.query) opts.query = uri.query;
  }

  this.secure = null != opts.secure ? opts.secure :
    (global.location && 'https:' == location.protocol);

  if (opts.host) {
    var pieces = opts.host.split(':');
    opts.hostname = pieces.shift();
    if (pieces.length) opts.port = pieces.pop();
  }

  this.agent = opts.agent || false;
  this.hostname = opts.hostname ||
    (global.location ? location.hostname : 'localhost');
  this.port = opts.port || (global.location && location.port ?
       location.port :
       (this.secure ? 443 : 80));
  this.query = opts.query || {};
  if ('string' == typeof this.query) this.query = util.qsParse(this.query);
  this.upgrade = false !== opts.upgrade;
  this.path = (opts.path || '/engine.io').replace(/\/$/, '') + '/';
  this.forceJSONP = !!opts.forceJSONP;
  this.forceBase64 = !!opts.forceBase64;
  this.timestampParam = opts.timestampParam || 't';
  this.timestampRequests = opts.timestampRequests;
  this.flashPath = opts.flashPath || '';
  this.transports = opts.transports || ['polling', 'websocket', 'flashsocket'];
  this.readyState = '';
  this.writeBuffer = [];
  this.callbackBuffer = [];
  this.policyPort = opts.policyPort || 843;
  this.rememberUpgrade = opts.rememberUpgrade || false;
  this.open();
  this.binaryType = null;
  this.onlyBinaryUpgrades = opts.onlyBinaryUpgrades;
}

Socket.priorWebsocketSuccess = false;

/**
 * Mix in `Emitter`.
 */

Emitter(Socket.prototype);

/**
 * Protocol version.
 *
 * @api public
 */

Socket.protocol = parser.protocol; // this is an int

/**
 * Expose deps for legacy compatibility
 * and standalone browser access.
 */

Socket.Socket = Socket;
Socket.Transport = _dereq_('./transport');
Socket.Emitter = _dereq_('./emitter');
Socket.transports = _dereq_('./transports');
Socket.util = _dereq_('./util');
Socket.parser = _dereq_('engine.io-parser');

/**
 * Creates transport of the given type.
 *
 * @param {String} transport name
 * @return {Transport}
 * @api private
 */

Socket.prototype.createTransport = function (name) {
  debug('creating transport "%s"', name);
  var query = clone(this.query);

  // append engine.io protocol identifier
  query.EIO = parser.protocol;

  // transport name
  query.transport = name;

  // session id if we already have one
  if (this.id) query.sid = this.id;

  var transport = new transports[name]({
    agent: this.agent,
    hostname: this.hostname,
    port: this.port,
    secure: this.secure,
    path: this.path,
    query: query,
    forceJSONP: this.forceJSONP,
    forceBase64: this.forceBase64,
    timestampRequests: this.timestampRequests,
    timestampParam: this.timestampParam,
    flashPath: this.flashPath,
    policyPort: this.policyPort,
    socket: this
  });

  return transport;
};

function clone (obj) {
  var o = {};
  for (var i in obj) {
    if (obj.hasOwnProperty(i)) {
      o[i] = obj[i];
    }
  }
  return o;
}

/**
 * Initializes transport to use and starts probe.
 *
 * @api private
 */
Socket.prototype.open = function () {
  var transport;
  if (this.rememberUpgrade && Socket.priorWebsocketSuccess && this.transports.indexOf('websocket') != -1) {
    transport = 'websocket';
  } else {
    transport = this.transports[0];
  }
  this.readyState = 'opening';
  var transport = this.createTransport(transport);
  transport.open();
  this.setTransport(transport);
};

/**
 * Sets the current transport. Disables the existing one (if any).
 *
 * @api private
 */

Socket.prototype.setTransport = function(transport){
  debug('setting transport %s', transport.name);
  var self = this;

  if (this.transport) {
    debug('clearing existing transport %s', this.transport.name);
    this.transport.removeAllListeners();
  }

  // set up transport
  this.transport = transport;

  // set up transport listeners
  transport
  .on('drain', function(){
    self.onDrain();
  })
  .on('packet', function(packet){
    self.onPacket(packet);
  })
  .on('error', function(e){
    self.onError(e);
  })
  .on('close', function(){
    self.onClose('transport close');
  });
};

/**
 * Probes a transport.
 *
 * @param {String} transport name
 * @api private
 */

Socket.prototype.probe = function (name) {
  debug('probing transport "%s"', name);
  var transport = this.createTransport(name, { probe: 1 })
    , failed = false
    , self = this;

  Socket.priorWebsocketSuccess = false;

  transport.once('open', function () {
    if (this.onlyBinaryUpgrades) {
      var upgradeLosesBinary = !this.supportsBinary && self.transport.supportsBinary;
      failed = failed || upgradeLosesBinary;
    }
    if (failed) return;

    debug('probe transport "%s" opened', name);
    transport.send([{ type: 'ping', data: 'probe' }]);
    transport.once('packet', function (msg) {
      if (failed) return;
      if ('pong' == msg.type && 'probe' == msg.data) {
        debug('probe transport "%s" pong', name);
        self.upgrading = true;
        self.emit('upgrading', transport);
        Socket.priorWebsocketSuccess = 'websocket' == transport.name;

        debug('pausing current transport "%s"', self.transport.name);
        self.transport.pause(function () {
          if (failed) return;
          if ('closed' == self.readyState || 'closing' == self.readyState) {
            return;
          }
          debug('changing transport and sending upgrade packet');
          transport.removeListener('error', onerror);
          self.setTransport(transport);
          transport.send([{ type: 'upgrade' }]);
          self.emit('upgrade', transport);
          transport = null;
          self.upgrading = false;
          self.flush();
        });
      } else {
        debug('probe transport "%s" failed', name);
        var err = new Error('probe error');
        err.transport = transport.name;
        self.emit('upgradeError', err);
      }
    });
  });

  transport.once('error', onerror);
  function onerror(err) {
    if (failed) return;

    // Any callback called by transport should be ignored since now
    failed = true;

    var error = new Error('probe error: ' + err);
    error.transport = transport.name;

    transport.close();
    transport = null;

    debug('probe transport "%s" failed because of error: %s', name, err);

    self.emit('upgradeError', error);
  }

  transport.open();

  this.once('close', function () {
    if (transport) {
      debug('socket closed prematurely - aborting probe');
      failed = true;
      transport.close();
      transport = null;
    }
  });

  this.once('upgrading', function (to) {
    if (transport && to.name != transport.name) {
      debug('"%s" works - aborting "%s"', to.name, transport.name);
      transport.close();
      transport = null;
    }
  });
};

/**
 * Called when connection is deemed open.
 *
 * @api public
 */

Socket.prototype.onOpen = function () {
  debug('socket open');
  this.readyState = 'open';
  Socket.priorWebsocketSuccess = 'websocket' == this.transport.name;
  this.emit('open');
  this.onopen && this.onopen.call(this);
  this.flush();

  // we check for `readyState` in case an `open`
  // listener already closed the socket
  if ('open' == this.readyState && this.upgrade && this.transport.pause) {
    debug('starting upgrade probes');
    for (var i = 0, l = this.upgrades.length; i < l; i++) {
      this.probe(this.upgrades[i]);
    }
  }
};

/**
 * Handles a packet.
 *
 * @api private
 */

Socket.prototype.onPacket = function (packet) {
  if ('opening' == this.readyState || 'open' == this.readyState) {
    debug('socket receive: type "%s", data "%s"', packet.type, packet.data);

    this.emit('packet', packet);

    // Socket is live - any packet counts
    this.emit('heartbeat');

    switch (packet.type) {
      case 'open':
        this.onHandshake(parsejson(packet.data));
        break;

      case 'pong':
        this.setPing();
        break;

      case 'error':
        var err = new Error('server error');
        err.code = packet.data;
        this.emit('error', err);
        break;

      case 'message':
        this.emit('data', packet.data);
        this.emit('message', packet.data);
        var event = { data: packet.data };
        event.toString = function () {
          return packet.data;
        };

        this.onmessage && this.onmessage.call(this, event);
        break;
    }
  } else {
    debug('packet received with socket readyState "%s"', this.readyState);
  }
};

/**
 * Called upon handshake completion.
 *
 * @param {Object} handshake obj
 * @api private
 */

Socket.prototype.onHandshake = function (data) {
  this.emit('handshake', data);
  this.id = data.sid;
  this.transport.query.sid = data.sid;
  this.upgrades = this.filterUpgrades(data.upgrades);
  this.pingInterval = data.pingInterval;
  this.pingTimeout = data.pingTimeout;
  this.onOpen();
  this.setPing();

  // Prolong liveness of socket on heartbeat
  this.removeListener('heartbeat', this.onHeartbeat);
  this.on('heartbeat', this.onHeartbeat);
};

/**
 * Resets ping timeout.
 *
 * @api private
 */

Socket.prototype.onHeartbeat = function (timeout) {
  clearTimeout(this.pingTimeoutTimer);
  var self = this;
  self.pingTimeoutTimer = setTimeout(function () {
    if ('closed' == self.readyState) return;
    self.onClose('ping timeout');
  }, timeout || (self.pingInterval + self.pingTimeout));
};

/**
 * Pings server every `this.pingInterval` and expects response
 * within `this.pingTimeout` or closes connection.
 *
 * @api private
 */

Socket.prototype.setPing = function () {
  var self = this;
  clearTimeout(self.pingIntervalTimer);
  self.pingIntervalTimer = setTimeout(function () {
    debug('writing ping packet - expecting pong within %sms', self.pingTimeout);
    self.ping();
    self.onHeartbeat(self.pingTimeout);
  }, self.pingInterval);
};

/**
* Sends a ping packet.
*
* @api public
*/

Socket.prototype.ping = function () {
  this.sendPacket('ping');
};

/**
 * Called on `drain` event
 *
 * @api private
 */

Socket.prototype.onDrain = function() {
  for (var i = 0; i < this.prevBufferLen; i++) {
    if (this.callbackBuffer[i]) {
      this.callbackBuffer[i]();
    }
  }

  this.writeBuffer.splice(0, this.prevBufferLen);
  this.callbackBuffer.splice(0, this.prevBufferLen);

  // setting prevBufferLen = 0 is very important
  // for example, when upgrading, upgrade packet is sent over,
  // and a nonzero prevBufferLen could cause problems on `drain`
  this.prevBufferLen = 0;

  if (this.writeBuffer.length == 0) {
    this.emit('drain');
  } else {
    this.flush();
  }
};

/**
 * Flush write buffers.
 *
 * @api private
 */

Socket.prototype.flush = function () {
  if ('closed' != this.readyState && this.transport.writable &&
    !this.upgrading && this.writeBuffer.length) {
    debug('flushing %d packets in socket', this.writeBuffer.length);
    this.transport.send(this.writeBuffer);
    // keep track of current length of writeBuffer
    // splice writeBuffer and callbackBuffer on `drain`
    this.prevBufferLen = this.writeBuffer.length;
    this.emit('flush');
  }
};

/**
 * Sends a message.
 *
 * @param {String} message.
 * @param {Function} callback function.
 * @return {Socket} for chaining.
 * @api public
 */

Socket.prototype.write =
Socket.prototype.send = function (msg, fn) {
  this.sendPacket('message', msg, fn);
  return this;
};

/**
 * Sends a packet.
 *
 * @param {String} packet type.
 * @param {String} data.
 * @param {Function} callback function.
 * @api private
 */

Socket.prototype.sendPacket = function (type, data, fn) {
  var packet = { type: type, data: data };
  this.emit('packetCreate', packet);
  this.writeBuffer.push(packet);
  this.callbackBuffer.push(fn);
  this.flush();
};

/**
 * Closes the connection.
 *
 * @api private
 */

Socket.prototype.close = function () {
  if ('opening' == this.readyState || 'open' == this.readyState) {
    this.onClose('forced close');
    debug('socket closing - telling transport to close');
    this.transport.close();
  }

  return this;
};

/**
 * Called upon transport error
 *
 * @api private
 */

Socket.prototype.onError = function (err) {
  debug('socket error %j', err);
  Socket.priorWebsocketSuccess = false;
  this.emit('error', err);
  this.onerror && this.onerror.call(this, err);
  this.onClose('transport error', err);
};

/**
 * Called upon transport close.
 *
 * @api private
 */

Socket.prototype.onClose = function (reason, desc) {
  if ('opening' == this.readyState || 'open' == this.readyState) {
    debug('socket close with reason: "%s"', reason);
    var self = this;

    // clear timers
    clearTimeout(this.pingIntervalTimer);
    clearTimeout(this.pingTimeoutTimer);

    // clean buffers in next tick, so developers can still
    // grab the buffers on `close` event
    setTimeout(function() {
      self.writeBuffer = [];
      self.callbackBuffer = [];
      self.prevBufferLen = 0;
    }, 0);

    // ignore further transport communication
    this.transport.removeAllListeners();

    // set ready state
    this.readyState = 'closed';

    // clear session id
    this.id = null;

    // emit close event
    this.emit('close', reason, desc);
    this.onclose && this.onclose.call(this);
  }
};

/**
 * Filters upgrades, returning only those matching client transports.
 *
 * @param {Array} server upgrades
 * @api private
 *
 */

Socket.prototype.filterUpgrades = function (upgrades) {
  var filteredUpgrades = [];
  for (var i = 0, j = upgrades.length; i<j; i++) {
    if (~index(this.transports, upgrades[i])) filteredUpgrades.push(upgrades[i]);
  }
  return filteredUpgrades;
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./emitter":2,"./transport":5,"./transports":7,"./util":12,"debug":15,"engine.io-parser":17,"indexof":24,"parsejson":25,"parseuri":26}],5:[function(_dereq_,module,exports){
/**
 * Module dependencies.
 */

var util = _dereq_('./util');
var parser = _dereq_('engine.io-parser');
var Emitter = _dereq_('./emitter');

/**
 * Module exports.
 */

module.exports = Transport;

/**
 * Transport abstract constructor.
 *
 * @param {Object} options.
 * @api private
 */

function Transport (opts) {
  this.path = opts.path;
  this.hostname = opts.hostname;
  this.port = opts.port;
  this.secure = opts.secure;
  this.query = opts.query;
  this.timestampParam = opts.timestampParam;
  this.timestampRequests = opts.timestampRequests;
  this.readyState = '';
  this.agent = opts.agent || false;
  this.socket = opts.socket;
}

/**
 * Mix in `Emitter`.
 */

Emitter(Transport.prototype);

/**
 * Emits an error.
 *
 * @param {String} str
 * @return {Transport} for chaining
 * @api public
 */

Transport.prototype.onError = function (msg, desc) {
  var err = new Error(msg);
  err.type = 'TransportError';
  err.description = desc;
  this.emit('error', err);
  return this;
};

/**
 * Opens the transport.
 *
 * @api public
 */

Transport.prototype.open = function () {
  if ('closed' == this.readyState || '' == this.readyState) {
    this.readyState = 'opening';
    this.doOpen();
  }

  return this;
};

/**
 * Closes the transport.
 *
 * @api private
 */

Transport.prototype.close = function () {
  if ('opening' == this.readyState || 'open' == this.readyState) {
    this.doClose();
    this.onClose();
  }

  return this;
};

/**
 * Sends multiple packets.
 *
 * @param {Array} packets
 * @api private
 */

Transport.prototype.send = function(packets){
  if ('open' == this.readyState) {
    this.write(packets);
  } else {
    throw new Error('Transport not open');
  }
};

/**
 * Called upon open
 *
 * @api private
 */

Transport.prototype.onOpen = function () {
  this.readyState = 'open';
  this.writable = true;
  this.emit('open');
};

/**
 * Called with data.
 *
 * @param {String} data
 * @api private
 */

Transport.prototype.onData = function (data) {
  this.onPacket(parser.decodePacket(data, this.socket.binaryType));
};

/**
 * Called with a decoded packet.
 */

Transport.prototype.onPacket = function (packet) {
  this.emit('packet', packet);
};

/**
 * Called upon close.
 *
 * @api private
 */

Transport.prototype.onClose = function () {
  this.readyState = 'closed';
  this.emit('close');
};

},{"./emitter":2,"./util":12,"engine.io-parser":17}],6:[function(_dereq_,module,exports){
(function (global){

/**
 * Module dependencies.
 */

var WS = _dereq_('./websocket');
var util = _dereq_('../util');
var debug = _dereq_('debug')('engine.io-client:flashsocket');

/**
 * Module exports.
 */

module.exports = FlashWS;

/**
 * Obfuscated key for Blue Coat.
 */

var xobject = global[['Active'].concat('Object').join('X')];

/**
 * FlashWS constructor.
 *
 * @api public
 */

function FlashWS(options){
  WS.call(this, options);
  this.flashPath = options.flashPath;
  this.policyPort = options.policyPort;
}

/**
 * Inherits from WebSocket.
 */

util.inherits(FlashWS, WS);

/**
 * Transport name.
 *
 * @api public
 */

FlashWS.prototype.name = 'flashsocket';

/*
 * FlashSockets only support binary as base64 encoded strings
 */

FlashWS.prototype.supportsBinary = false;

/**
 * Opens the transport.
 *
 * @api public
 */

FlashWS.prototype.doOpen = function(){
  if (!this.check()) {
    // let the probe timeout
    return;
  }

  // instrument websocketjs logging
  function log(type){
    return function(){
      var str = Array.prototype.join.call(arguments, ' ');
      debug('[websocketjs %s] %s', type, str);
    };
  }

  global.WEB_SOCKET_LOGGER = { log: log('debug'), error: log('error') };
  global.WEB_SOCKET_SUPPRESS_CROSS_DOMAIN_SWF_ERROR = true;
  global.WEB_SOCKET_DISABLE_AUTO_INITIALIZATION = true;

  if (!global.WEB_SOCKET_SWF_LOCATION) {
    global.WEB_SOCKET_SWF_LOCATION = this.flashPath + 'WebSocketMainInsecure.swf';
  }

  // dependencies
  var deps = [this.flashPath + 'web_socket.js'];

  if (!global.swfobject) {
    deps.unshift(this.flashPath + 'swfobject.js');
  }

  var self = this;

  load(deps, function(){
    self.ready(function(){
      WebSocket.__addTask(function () {
        self.ws = new WebSocket(self.uri());
        self.addEventListeners();
      });
    });
  });
};

/**
 * Override to prevent closing uninitialized flashsocket.
 *
 * @api private
 */

FlashWS.prototype.doClose = function(){
  if (!this.ws) return;
  var self = this;
  WebSocket.__addTask(function(){
    WS.prototype.doClose.call(self);
  });
};

/**
 * Writes to the Flash socket.
 *
 * @api private
 */

FlashWS.prototype.write = function(){
  var self = this, args = arguments;
  WebSocket.__addTask(function(){
    WS.prototype.write.apply(self, args);
  });
};

/**
 * Called upon dependencies are loaded.
 *
 * @api private
 */

FlashWS.prototype.ready = function(fn){
  if (typeof WebSocket == 'undefined' ||
    !('__initialize' in WebSocket) || !global.swfobject) {
    return;
  }

  if (global.swfobject.getFlashPlayerVersion().major < 10) {
    return;
  }

  function init () {
    // only start downloading the swf file when
    // we checked that this browser actually supports it
    if (!FlashWS.loaded) {
      if (843 != self.policyPort) {
        var policy = 'xmlsocket://' + self.hostname + ':' + self.policyPort;
        WebSocket.loadFlashPolicyFile(policy);
      }

      WebSocket.__initialize();
      FlashWS.loaded = true;
    }

    fn.call(self);
  }

  var self = this;
  if (document.body) {
    return init();
  }

  util.load(init);
};

/**
 * Feature detection for flashsocket.
 *
 * @return {Boolean} whether this transport is available.
 * @api public
 */

FlashWS.prototype.check = function(){
  if ('undefined' == typeof window) {
    return false;
  }

  if (typeof WebSocket != 'undefined' && !('__initialize' in WebSocket)) {
    return false;
  }

  if (xobject) {
    var control = null;
    try {
      control = new xobject('ShockwaveFlash.ShockwaveFlash');
    } catch (e) { }
    if (control) {
      return true;
    }
  } else {
    for (var i = 0, l = navigator.plugins.length; i < l; i++) {
      for (var j = 0, m = navigator.plugins[i].length; j < m; j++) {
        if (navigator.plugins[i][j].description == 'Shockwave Flash') {
          return true;
        }
      }
    }
  }

  return false;
};

/**
 * Lazy loading of scripts.
 * Based on $script by Dustin Diaz - MIT
 */

var scripts = {};

/**
 * Injects a script. Keeps tracked of injected ones.
 *
 * @param {String} path
 * @param {Function} callback
 * @api private
 */

function create(path, fn){
  if (scripts[path]) return fn();

  var el = document.createElement('script');
  var loaded = false;

  debug('loading "%s"', path);
  el.onload = el.onreadystatechange = function(){
    if (loaded || scripts[path]) return;
    var rs = el.readyState;
    if (!rs || 'loaded' == rs || 'complete' == rs) {
      debug('loaded "%s"', path);
      el.onload = el.onreadystatechange = null;
      loaded = true;
      scripts[path] = true;
      fn();
    }
  };

  el.async = 1;
  el.src = path;

  var head = document.getElementsByTagName('head')[0];
  head.insertBefore(el, head.firstChild);
}

/**
 * Loads scripts and fires a callback.
 *
 * @param {Array} paths
 * @param {Function} callback
 */

function load(arr, fn){
  function process(i){
    if (!arr[i]) return fn();
    create(arr[i], function () {
      process(++i);
    });
  }

  process(0);
}

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../util":12,"./websocket":11,"debug":15}],7:[function(_dereq_,module,exports){
(function (global){

/**
 * Module dependencies
 */

var XMLHttpRequest = _dereq_('xmlhttprequest')
  , XHR = _dereq_('./polling-xhr')
  , JSONP = _dereq_('./polling-jsonp')
  , websocket = _dereq_('./websocket')
  , flashsocket = _dereq_('./flashsocket')

/**
 * Export transports.
 */

exports.polling = polling;
exports.websocket = websocket;
exports.flashsocket = flashsocket;

/**
 * Polling transport polymorphic constructor.
 * Decides on xhr vs jsonp based on feature detection.
 *
 * @api private
 */

function polling (opts) {
  var xhr
    , xd = false;

  if (global.location) {
    var isSSL = 'https:' == location.protocol;
    var port = location.port;

    // some user agents have empty `location.port`
    if (!port) {
      port = isSSL ? 443 : 80;
    }

    xd = opts.hostname != location.hostname || port != opts.port;
  }

  opts.xdomain = xd;
  xhr = new XMLHttpRequest(opts);

  if (xhr && !opts.forceJSONP) {
    return new XHR(opts);
  } else {
    return new JSONP(opts);
  }
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./flashsocket":6,"./polling-jsonp":8,"./polling-xhr":9,"./websocket":11,"xmlhttprequest":13}],8:[function(_dereq_,module,exports){
(function (global){

/**
 * Module requirements.
 */

var Polling = _dereq_('./polling');
var util = _dereq_('../util');

/**
 * Module exports.
 */

module.exports = JSONPPolling;

/**
 * Cached regular expressions.
 */

var rNewline = /\n/g;

/**
 * Global JSONP callbacks.
 */

var callbacks;

/**
 * Callbacks count.
 */

var index = 0;

/**
 * Noop.
 */

function empty () { }

/**
 * JSONP Polling constructor.
 *
 * @param {Object} opts.
 * @api public
 */

function JSONPPolling (opts) {
  Polling.call(this, opts);

  // define global callbacks array if not present
  // we do this here (lazily) to avoid unneeded global pollution
  if (!callbacks) {
    // we need to consider multiple engines in the same page
    if (!global.___eio) global.___eio = [];
    callbacks = global.___eio;
  }

  // callback identifier
  this.index = callbacks.length;

  // add callback to jsonp global
  var self = this;
  callbacks.push(function (msg) {
    self.onData(msg);
  });

  // append to query string
  this.query.j = this.index;
}

/**
 * Inherits from Polling.
 */

util.inherits(JSONPPolling, Polling);

/*
 * JSONP only supports binary as base64 encoded strings
 */

JSONPPolling.prototype.supportsBinary = false;

/**
 * Closes the socket
 *
 * @api private
 */

JSONPPolling.prototype.doClose = function () {
  if (this.script) {
    this.script.parentNode.removeChild(this.script);
    this.script = null;
  }

  if (this.form) {
    this.form.parentNode.removeChild(this.form);
    this.form = null;
  }

  Polling.prototype.doClose.call(this);
};

/**
 * Starts a poll cycle.
 *
 * @api private
 */

JSONPPolling.prototype.doPoll = function () {
	var self = this;
  var script = document.createElement('script');

  if (this.script) {
    this.script.parentNode.removeChild(this.script);
    this.script = null;
  }

  script.async = true;
  script.src = this.uri();
  script.onerror = function(e){
    self.onError('jsonp poll error',e);
  };

  var insertAt = document.getElementsByTagName('script')[0];
  insertAt.parentNode.insertBefore(script, insertAt);
  this.script = script;


  if (util.ua.gecko) {
    setTimeout(function () {
      var iframe = document.createElement('iframe');
      document.body.appendChild(iframe);
      document.body.removeChild(iframe);
    }, 100);
  }
};

/**
 * Writes with a hidden iframe.
 *
 * @param {String} data to send
 * @param {Function} called upon flush.
 * @api private
 */

JSONPPolling.prototype.doWrite = function (data, fn) {
  var self = this;

  if (!this.form) {
    var form = document.createElement('form');
    var area = document.createElement('textarea');
    var id = this.iframeId = 'eio_iframe_' + this.index;
    var iframe;

    form.className = 'socketio';
    form.style.position = 'absolute';
    form.style.top = '-1000px';
    form.style.left = '-1000px';
    form.target = id;
    form.method = 'POST';
    form.setAttribute('accept-charset', 'utf-8');
    area.name = 'd';
    form.appendChild(area);
    document.body.appendChild(form);

    this.form = form;
    this.area = area;
  }

  this.form.action = this.uri();

  function complete () {
    initIframe();
    fn();
  }

  function initIframe () {
    if (self.iframe) {
      try {
        self.form.removeChild(self.iframe);
      } catch (e) {
        self.onError('jsonp polling iframe removal error', e);
      }
    }

    try {
      // ie6 dynamic iframes with target="" support (thanks Chris Lambacher)
      var html = '<iframe src="javascript:0" name="'+ self.iframeId +'">';
      iframe = document.createElement(html);
    } catch (e) {
      iframe = document.createElement('iframe');
      iframe.name = self.iframeId;
      iframe.src = 'javascript:0';
    }

    iframe.id = self.iframeId;

    self.form.appendChild(iframe);
    self.iframe = iframe;
  }

  initIframe();

  // escape \n to prevent it from being converted into \r\n by some UAs
  this.area.value = data.replace(rNewline, '\\n');

  try {
    this.form.submit();
  } catch(e) {}

  if (this.iframe.attachEvent) {
    this.iframe.onreadystatechange = function(){
      if (self.iframe.readyState == 'complete') {
        complete();
      }
    };
  } else {
    this.iframe.onload = complete;
  }
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../util":12,"./polling":10}],9:[function(_dereq_,module,exports){
(function (global){
/**
 * Module requirements.
 */

var XMLHttpRequest = _dereq_('xmlhttprequest');
var Polling = _dereq_('./polling');
var util = _dereq_('../util');
var Emitter = _dereq_('../emitter');
var debug = _dereq_('debug')('engine.io-client:polling-xhr');

/**
 * Module exports.
 */

module.exports = XHR;
module.exports.Request = Request;

/**
 * Obfuscated key for Blue Coat.
 */

var hasAttachEvent = global.document && global.document.attachEvent;

/**
 * Empty function
 */

function empty(){}

/**
 * XHR Polling constructor.
 *
 * @param {Object} opts
 * @api public
 */

function XHR(opts){
  Polling.call(this, opts);

  if (global.location) {
    var isSSL = 'https:' == location.protocol;
    var port = location.port;

    // some user agents have empty `location.port`
    if (!port) {
      port = isSSL ? 443 : 80;
    }

    this.xd = opts.hostname != global.location.hostname ||
      port != opts.port;
  }
}

/**
 * Inherits from Polling.
 */

util.inherits(XHR, Polling);

/**
 * XHR supports binary
 */

XHR.prototype.supportsBinary = true;

/**
 * Creates a request.
 *
 * @param {String} method
 * @api private
 */

XHR.prototype.request = function(opts){
  opts = opts || {};
  opts.uri = this.uri();
  opts.xd = this.xd;
  opts.agent = this.agent || false;
  opts.supportsBinary = this.supportsBinary;
  return new Request(opts);
};

/**
 * Sends data.
 *
 * @param {String} data to send.
 * @param {Function} called upon flush.
 * @api private
 */

XHR.prototype.doWrite = function(data, fn){
  var isBinary = typeof data !== 'string' && data !== undefined;
  var req = this.request({ method: 'POST', data: data, isBinary: isBinary });
  var self = this;
  req.on('success', fn);
  req.on('error', function(err){
    self.onError('xhr post error', err);
  });
  this.sendXhr = req;
};

/**
 * Starts a poll cycle.
 *
 * @api private
 */

XHR.prototype.doPoll = function(){
  debug('xhr poll');
  var req = this.request();
  var self = this;
  req.on('data', function(data){
    self.onData(data);
  });
  req.on('error', function(err){
    self.onError('xhr poll error', err);
  });
  this.pollXhr = req;
};

/**
 * Request constructor
 *
 * @param {Object} options
 * @api public
 */

function Request(opts){
  this.method = opts.method || 'GET';
  this.uri = opts.uri;
  this.xd = !!opts.xd;
  this.async = false !== opts.async;
  this.data = undefined != opts.data ? opts.data : null;
  this.agent = opts.agent;
  this.create(opts.isBinary, opts.supportsBinary);
}

/**
 * Mix in `Emitter`.
 */

Emitter(Request.prototype);

/**
 * Creates the XHR object and sends the request.
 *
 * @api private
 */

Request.prototype.create = function(isBinary, supportsBinary){
  var xhr = this.xhr = new XMLHttpRequest({ agent: this.agent, xdomain: this.xd });
  var self = this;

  try {
    debug('xhr open %s: %s', this.method, this.uri);
    xhr.open(this.method, this.uri, this.async);
    if (supportsBinary) {
      // This has to be done after open because Firefox is stupid
      // http://stackoverflow.com/questions/13216903/get-binary-data-with-xmlhttprequest-in-a-firefox-extension
      xhr.responseType = 'arraybuffer';
    }

    if ('POST' == this.method) {
      try {
        if (isBinary) {
          xhr.setRequestHeader('Content-type', 'application/octet-stream');
        } else {
          xhr.setRequestHeader('Content-type', 'text/plain;charset=UTF-8');
        }
      } catch (e) {}
    }

    // ie6 check
    if ('withCredentials' in xhr) {
      xhr.withCredentials = true;
    }

    xhr.onreadystatechange = function(){
      var data;

      try {
        if (4 != xhr.readyState) return;
        if (200 == xhr.status || 1223 == xhr.status) {
          var contentType = xhr.getResponseHeader('Content-Type');
          if (contentType === 'application/octet-stream') {
            data = xhr.response;
          } else {
            if (!supportsBinary) {
              data = xhr.responseText;
            } else {
              data = 'ok';
            }
          }
        } else {
          // make sure the `error` event handler that's user-set
          // does not throw in the same tick and gets caught here
          setTimeout(function(){
            self.onError(xhr.status);
          }, 0);
        }
      } catch (e) {
        self.onError(e);
      }

      if (null != data) {
        self.onData(data);
      }
    };

    debug('xhr data %s', this.data);
    xhr.send(this.data);
  } catch (e) {
    // Need to defer since .create() is called directly fhrom the constructor
    // and thus the 'error' event can only be only bound *after* this exception
    // occurs.  Therefore, also, we cannot throw here at all.
    setTimeout(function() {
      self.onError(e);
    }, 0);
    return;
  }

  if (hasAttachEvent) {
    this.index = Request.requestsCount++;
    Request.requests[this.index] = this;
  }
};

/**
 * Called upon successful response.
 *
 * @api private
 */

Request.prototype.onSuccess = function(){
  this.emit('success');
  this.cleanup();
};

/**
 * Called if we have data.
 *
 * @api private
 */

Request.prototype.onData = function(data){
  this.emit('data', data);
  this.onSuccess();
};

/**
 * Called upon error.
 *
 * @api private
 */

Request.prototype.onError = function(err){
  this.emit('error', err);
  this.cleanup();
};

/**
 * Cleans up house.
 *
 * @api private
 */

Request.prototype.cleanup = function(){
  if ('undefined' == typeof this.xhr ) {
    return;
  }
  // xmlhttprequest
  this.xhr.onreadystatechange = empty;

  try {
    this.xhr.abort();
  } catch(e) {}

  if (hasAttachEvent) {
    delete Request.requests[this.index];
  }

  this.xhr = null;
};

/**
 * Aborts the request.
 *
 * @api public
 */

Request.prototype.abort = function(){
  this.cleanup();
};

/**
 * Cleanup is needed for old versions of IE
 * that leak memory unless we abort request before unload.
 */

if (hasAttachEvent) {
  Request.requestsCount = 0;
  Request.requests = {};
  global.attachEvent('onunload', unloadHandler);
}

function unloadHandler() {
  for (var i in Request.requests) {
    if (Request.requests.hasOwnProperty(i)) {
      Request.requests[i].abort();
    }
  }
}

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../emitter":2,"../util":12,"./polling":10,"debug":15,"xmlhttprequest":13}],10:[function(_dereq_,module,exports){
(function (global){
/**
 * Module dependencies.
 */

var Transport = _dereq_('../transport');
var util = _dereq_('../util');
var parser = _dereq_('engine.io-parser');
var debug = _dereq_('debug')('engine.io-client:polling');

/**
 * Module exports.
 */

module.exports = Polling;

/**
 * Is XHR2 supported?
 */

var hasXHR2 = (function() {
  var XMLHttpRequest = _dereq_('xmlhttprequest');
  var xhr = new XMLHttpRequest({ agent: this.agent, xdomain: false });
  return null != xhr.responseType;
})();

/**
 * Polling interface.
 *
 * @param {Object} opts
 * @api private
 */

function Polling(opts){
  var forceBase64 = (opts && opts.forceBase64);
  if (!hasXHR2 || forceBase64) {
    this.supportsBinary = false;
  }
  Transport.call(this, opts);
}

/**
 * Inherits from Transport.
 */

util.inherits(Polling, Transport);

/**
 * Transport name.
 */

Polling.prototype.name = 'polling';

/**
 * Opens the socket (triggers polling). We write a PING message to determine
 * when the transport is open.
 *
 * @api private
 */

Polling.prototype.doOpen = function(){
  this.poll();
};

/**
 * Pauses polling.
 *
 * @param {Function} callback upon buffers are flushed and transport is paused
 * @api private
 */

Polling.prototype.pause = function(onPause){
  var pending = 0;
  var self = this;

  this.readyState = 'pausing';

  function pause(){
    debug('paused');
    self.readyState = 'paused';
    onPause();
  }

  if (this.polling || !this.writable) {
    var total = 0;

    if (this.polling) {
      debug('we are currently polling - waiting to pause');
      total++;
      this.once('pollComplete', function(){
        debug('pre-pause polling complete');
        --total || pause();
      });
    }

    if (!this.writable) {
      debug('we are currently writing - waiting to pause');
      total++;
      this.once('drain', function(){
        debug('pre-pause writing complete');
        --total || pause();
      });
    }
  } else {
    pause();
  }
};

/**
 * Starts polling cycle.
 *
 * @api public
 */

Polling.prototype.poll = function(){
  debug('polling');
  this.polling = true;
  this.doPoll();
  this.emit('poll');
};

/**
 * Overloads onData to detect payloads.
 *
 * @api private
 */

Polling.prototype.onData = function(data){
  var self = this;
  debug('polling got data %s', data);
  var callback = function(packet, index, total) {
    // if its the first message we consider the transport open
    if ('opening' == self.readyState) {
      self.onOpen();
    }

    // if its a close packet, we close the ongoing requests
    if ('close' == packet.type) {
      self.onClose();
      return false;
    }

    // otherwise bypass onData and handle the message
    self.onPacket(packet);
  };

  // decode payload
  parser.decodePayload(data, this.socket.binaryType, callback);

  // if an event did not trigger closing
  if ('closed' != this.readyState) {
    // if we got data we're not polling
    this.polling = false;
    this.emit('pollComplete');

    if ('open' == this.readyState) {
      this.poll();
    } else {
      debug('ignoring poll - transport state "%s"', this.readyState);
    }
  }
};

/**
 * For polling, send a close packet.
 *
 * @api private
 */

Polling.prototype.doClose = function(){
  var self = this;

  function close(){
    debug('writing close packet');
    self.write([{ type: 'close' }]);
  }

  if ('open' == this.readyState) {
    debug('transport open - closing');
    close();
  } else {
    // in case we're trying to close while
    // handshaking is in progress (GH-164)
    debug('transport not open - deferring close');
    this.once('open', close);
  }
};

/**
 * Writes a packets payload.
 *
 * @param {Array} data packets
 * @param {Function} drain callback
 * @api private
 */

Polling.prototype.write = function(packets){
  var self = this;
  this.writable = false;
  var callbackfn = function() {
    self.writable = true;
    self.emit('drain');
  };

  var self = this;
  parser.encodePayload(packets, this.supportsBinary, function(data) {
    self.doWrite(data, callbackfn);
  });
};

/**
 * Generates uri for connection.
 *
 * @api private
 */

Polling.prototype.uri = function(){
  var query = this.query || {};
  var schema = this.secure ? 'https' : 'http';
  var port = '';

  // cache busting is forced for IE / android / iOS6 ಠ_ಠ
  if ('ActiveXObject' in global
    || util.ua.chromeframe
    || util.ua.android
    || util.ua.ios6
    || this.timestampRequests) {
    if (false !== this.timestampRequests) {
      query[this.timestampParam] = +new Date;
    }
  }

  if (!this.supportsBinary && !query.sid) {
    query.b64 = 1;
  }

  query = util.qs(query);

  // avoid port if default for schema
  if (this.port && (('https' == schema && this.port != 443) ||
     ('http' == schema && this.port != 80))) {
    port = ':' + this.port;
  }

  // prepend ? to query
  if (query.length) {
    query = '?' + query;
  }

  return schema + '://' + this.hostname + port + this.path + query;
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../transport":5,"../util":12,"debug":15,"engine.io-parser":17,"xmlhttprequest":13}],11:[function(_dereq_,module,exports){
/**
 * Module dependencies.
 */

var Transport = _dereq_('../transport');
var parser = _dereq_('engine.io-parser');
var util = _dereq_('../util');
var debug = _dereq_('debug')('engine.io-client:websocket');

/**
 * `ws` exposes a WebSocket-compatible interface in
 * Node, or the `WebSocket` or `MozWebSocket` globals
 * in the browser.
 */

var WebSocket = _dereq_('ws');

/**
 * Module exports.
 */

module.exports = WS;

/**
 * WebSocket transport constructor.
 *
 * @api {Object} connection options
 * @api public
 */

function WS(opts){
  var forceBase64 = (opts && opts.forceBase64);
  if (forceBase64) {
    this.supportsBinary = false;
  }
  Transport.call(this, opts);
}

/**
 * Inherits from Transport.
 */

util.inherits(WS, Transport);

/**
 * Transport name.
 *
 * @api public
 */

WS.prototype.name = 'websocket';

/*
 * WebSockets support binary
 */

WS.prototype.supportsBinary = true;

/**
 * Opens socket.
 *
 * @api private
 */

WS.prototype.doOpen = function(){
  if (!this.check()) {
    // let probe timeout
    return;
  }

  var self = this;
  var uri = this.uri();
  var protocols = void(0);
  var opts = { agent: this.agent };

  this.ws = new WebSocket(uri, protocols, opts);

  if (this.ws.binaryType === undefined) {
    this.supportsBinary = false;
  }

  this.ws.binaryType = 'arraybuffer';
  this.addEventListeners();
};

/**
 * Adds event listeners to the socket
 *
 * @api private
 */

WS.prototype.addEventListeners = function(){
  var self = this;

  this.ws.onopen = function(){
    self.onOpen();
  };
  this.ws.onclose = function(){
    self.onClose();
  };
  this.ws.onmessage = function(ev){
    self.onData(ev.data);
  };
  this.ws.onerror = function(e){
    self.onError('websocket error', e);
  };
};

/**
 * Override `onData` to use a timer on iOS.
 * See: https://gist.github.com/mloughran/2052006
 *
 * @api private
 */

if ('undefined' != typeof navigator
  && /iPad|iPhone|iPod/i.test(navigator.userAgent)) {
  WS.prototype.onData = function(data){
    var self = this;
    setTimeout(function(){
      Transport.prototype.onData.call(self, data);
    }, 0);
  };
}

/**
 * Writes data to socket.
 *
 * @param {Array} array of packets.
 * @api private
 */

WS.prototype.write = function(packets){
  var self = this;
  this.writable = false;
  // encodePacket efficient as it uses WS framing
  // no need for encodePayload
  for (var i = 0, l = packets.length; i < l; i++) {
    parser.encodePacket(packets[i], this.supportsBinary, function(data) {
      self.ws.send(data);
    });
  }

  function ondrain() {
    self.writable = true;
    self.emit('drain');
  }
  // fake drain
  // defer to next tick to allow Socket to clear writeBuffer
  setTimeout(ondrain, 0);
};

/**
 * Called upon close
 *
 * @api private
 */

WS.prototype.onClose = function(){
  Transport.prototype.onClose.call(this);
};

/**
 * Closes socket.
 *
 * @api private
 */

WS.prototype.doClose = function(){
  if (typeof this.ws !== 'undefined') {
    this.ws.close();
  }
};

/**
 * Generates uri for connection.
 *
 * @api private
 */

WS.prototype.uri = function(){
  var query = this.query || {};
  var schema = this.secure ? 'wss' : 'ws';
  var port = '';

  // avoid port if default for schema
  if (this.port && (('wss' == schema && this.port != 443)
    || ('ws' == schema && this.port != 80))) {
    port = ':' + this.port;
  }

  // append timestamp to URI
  if (this.timestampRequests) {
    query[this.timestampParam] = +new Date;
  }

  // communicate binary support capabilities
  if (!this.supportsBinary) {
    query.b64 = 1;
  }

  query = util.qs(query);

  // prepend ? to query
  if (query.length) {
    query = '?' + query;
  }

  return schema + '://' + this.hostname + port + this.path + query;
};

/**
 * Feature detection for WebSocket.
 *
 * @return {Boolean} whether this transport is available.
 * @api public
 */

WS.prototype.check = function(){
  return !!WebSocket && !('__initialize' in WebSocket && this.name === WS.prototype.name);
};

},{"../transport":5,"../util":12,"debug":15,"engine.io-parser":17,"ws":27}],12:[function(_dereq_,module,exports){
(function (global){

/**
 * Status of page load.
 */

var pageLoaded = false;

/**
 * Inheritance.
 *
 * @param {Function} ctor a
 * @param {Function} ctor b
 * @api private
 */

exports.inherits = function inherits (a, b) {
  function c () { }
  c.prototype = b.prototype;
  a.prototype = new c;
};

/**
 * Object.keys
 */

exports.keys = Object.keys || function (obj) {
  var ret = [];
  var has = Object.prototype.hasOwnProperty;

  for (var i in obj) {
    if (has.call(obj, i)) {
      ret.push(i);
    }
  }

  return ret;
};

/**
 * Adds an event.
 *
 * @api private
 */

exports.on = function (element, event, fn, capture) {
  if (element.attachEvent) {
    element.attachEvent('on' + event, fn);
  } else if (element.addEventListener) {
    element.addEventListener(event, fn, capture);
  }
};

/**
 * Load utility.
 *
 * @api private
 */

exports.load = function (fn) {
  if (global.document && document.readyState === 'complete' || pageLoaded) {
    return fn();
  }

  exports.on(global, 'load', fn, false);
};

/**
 * Change the internal pageLoaded value.
 */

if ('undefined' != typeof window) {
  exports.load(function () {
    pageLoaded = true;
  });
}

/**
 * UA / engines detection namespace.
 *
 * @namespace
 */

exports.ua = {};

/**
 * Detect webkit.
 *
 * @api private
 */

exports.ua.webkit = 'undefined' != typeof navigator &&
  /webkit/i.test(navigator.userAgent);

/**
 * Detect gecko.
 *
 * @api private
 */

exports.ua.gecko = 'undefined' != typeof navigator &&
  /gecko/i.test(navigator.userAgent);

/**
 * Detect android;
 */

exports.ua.android = 'undefined' != typeof navigator &&
  /android/i.test(navigator.userAgent);

/**
 * Detect iOS.
 */

exports.ua.ios = 'undefined' != typeof navigator &&
  /^(iPad|iPhone|iPod)$/.test(navigator.platform);
exports.ua.ios6 = exports.ua.ios && /OS 6_/.test(navigator.userAgent);

/**
 * Detect Chrome Frame.
 */

exports.ua.chromeframe = Boolean(global.externalHost);

/**
 * Compiles a querystring
 *
 * @param {Object}
 * @api private
 */

exports.qs = function (obj) {
  var str = '';

  for (var i in obj) {
    if (obj.hasOwnProperty(i)) {
      if (str.length) str += '&';
      str += encodeURIComponent(i) + '=' + encodeURIComponent(obj[i]);
    }
  }

  return str;
};

/**
 * Parses a simple querystring.
 *
 * @param {String} qs
 * @api private
 */

exports.qsParse = function(qs){
  var qry = {};
  var pairs = qs.split('&');
  for (var i = 0, l = pairs.length; i < l; i++) {
    var pair = pairs[i].split('=');
    qry[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
  }
  return qry;
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],13:[function(_dereq_,module,exports){
// browser shim for xmlhttprequest module
var hasCORS = _dereq_('has-cors');

module.exports = function(opts) {
  var xdomain = opts.xdomain;

  // XMLHttpRequest can be disabled on IE
  try {
    if ('undefined' != typeof XMLHttpRequest && (!xdomain || hasCORS)) {
      return new XMLHttpRequest();
    }
  } catch (e) { }

  if (!xdomain) {
    try {
      return new ActiveXObject('Microsoft.XMLHTTP');
    } catch(e) { }
  }
}

},{"has-cors":22}],14:[function(_dereq_,module,exports){
(function (global){
/**
 * Create a blob builder even when vendor prefixes exist
 */

var BlobBuilder = global.BlobBuilder
  || global.WebKitBlobBuilder
  || global.MSBlobBuilder
  || global.MozBlobBuilder;

/**
 * Check if Blob constructor is supported
 */

var blobSupported = (function() {
  try {
    var b = new Blob(['hi']);
    return b.size == 2;
  } catch(e) {
    return false;
  }
})();

/**
 * Check if BlobBuilder is supported
 */

var blobBuilderSupported = BlobBuilder
  && BlobBuilder.prototype.append
  && BlobBuilder.prototype.getBlob;

function BlobBuilderConstructor(ary, options) {
  options = options || {};

  var bb = new BlobBuilder();
  for (var i = 0; i < ary.length; i++) {
    bb.append(ary[i]);
  }
  return (options.type) ? bb.getBlob(options.type) : bb.getBlob();
};

module.exports = (function() {
  if (blobSupported) {
    return global.Blob;
  } else if (blobBuilderSupported) {
    return BlobBuilderConstructor;
  } else {
    return undefined;
  }
})();

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],15:[function(_dereq_,module,exports){

/**
 * Expose `debug()` as the module.
 */

module.exports = debug;

/**
 * Create a debugger with the given `name`.
 *
 * @param {String} name
 * @return {Type}
 * @api public
 */

function debug(name) {
  if (!debug.enabled(name)) return function(){};

  return function(fmt){
    fmt = coerce(fmt);

    var curr = new Date;
    var ms = curr - (debug[name] || curr);
    debug[name] = curr;

    fmt = name
      + ' '
      + fmt
      + ' +' + debug.humanize(ms);

    // This hackery is required for IE8
    // where `console.log` doesn't have 'apply'
    window.console
      && console.log
      && Function.prototype.apply.call(console.log, console, arguments);
  }
}

/**
 * The currently active debug mode names.
 */

debug.names = [];
debug.skips = [];

/**
 * Enables a debug mode by name. This can include modes
 * separated by a colon and wildcards.
 *
 * @param {String} name
 * @api public
 */

debug.enable = function(name) {
  try {
    localStorage.debug = name;
  } catch(e){}

  var split = (name || '').split(/[\s,]+/)
    , len = split.length;

  for (var i = 0; i < len; i++) {
    name = split[i].replace('*', '.*?');
    if (name[0] === '-') {
      debug.skips.push(new RegExp('^' + name.substr(1) + '$'));
    }
    else {
      debug.names.push(new RegExp('^' + name + '$'));
    }
  }
};

/**
 * Disable debug output.
 *
 * @api public
 */

debug.disable = function(){
  debug.enable('');
};

/**
 * Humanize the given `ms`.
 *
 * @param {Number} m
 * @return {String}
 * @api private
 */

debug.humanize = function(ms) {
  var sec = 1000
    , min = 60 * 1000
    , hour = 60 * min;

  if (ms >= hour) return (ms / hour).toFixed(1) + 'h';
  if (ms >= min) return (ms / min).toFixed(1) + 'm';
  if (ms >= sec) return (ms / sec | 0) + 's';
  return ms + 'ms';
};

/**
 * Returns true if the given mode name is enabled, false otherwise.
 *
 * @param {String} name
 * @return {Boolean}
 * @api public
 */

debug.enabled = function(name) {
  for (var i = 0, len = debug.skips.length; i < len; i++) {
    if (debug.skips[i].test(name)) {
      return false;
    }
  }
  for (var i = 0, len = debug.names.length; i < len; i++) {
    if (debug.names[i].test(name)) {
      return true;
    }
  }
  return false;
};

/**
 * Coerce `val`.
 */

function coerce(val) {
  if (val instanceof Error) return val.stack || val.message;
  return val;
}

// persist

try {
  if (window.localStorage) debug.enable(localStorage.debug);
} catch(e){}

},{}],16:[function(_dereq_,module,exports){

/**
 * Module dependencies.
 */

var index = _dereq_('indexof');

/**
 * Expose `Emitter`.
 */

module.exports = Emitter;

/**
 * Initialize a new `Emitter`.
 *
 * @api public
 */

function Emitter(obj) {
  if (obj) return mixin(obj);
};

/**
 * Mixin the emitter properties.
 *
 * @param {Object} obj
 * @return {Object}
 * @api private
 */

function mixin(obj) {
  for (var key in Emitter.prototype) {
    obj[key] = Emitter.prototype[key];
  }
  return obj;
}

/**
 * Listen on the given `event` with `fn`.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.on = function(event, fn){
  this._callbacks = this._callbacks || {};
  (this._callbacks[event] = this._callbacks[event] || [])
    .push(fn);
  return this;
};

/**
 * Adds an `event` listener that will be invoked a single
 * time then automatically removed.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.once = function(event, fn){
  var self = this;
  this._callbacks = this._callbacks || {};

  function on() {
    self.off(event, on);
    fn.apply(this, arguments);
  }

  fn._off = on;
  this.on(event, on);
  return this;
};

/**
 * Remove the given callback for `event` or all
 * registered callbacks.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */

Emitter.prototype.off =
Emitter.prototype.removeListener =
Emitter.prototype.removeAllListeners = function(event, fn){
  this._callbacks = this._callbacks || {};

  // all
  if (0 == arguments.length) {
    this._callbacks = {};
    return this;
  }

  // specific event
  var callbacks = this._callbacks[event];
  if (!callbacks) return this;

  // remove all handlers
  if (1 == arguments.length) {
    delete this._callbacks[event];
    return this;
  }

  // remove specific handler
  var i = index(callbacks, fn._off || fn);
  if (~i) callbacks.splice(i, 1);
  return this;
};

/**
 * Emit `event` with the given args.
 *
 * @param {String} event
 * @param {Mixed} ...
 * @return {Emitter}
 */

Emitter.prototype.emit = function(event){
  this._callbacks = this._callbacks || {};
  var args = [].slice.call(arguments, 1)
    , callbacks = this._callbacks[event];

  if (callbacks) {
    callbacks = callbacks.slice(0);
    for (var i = 0, len = callbacks.length; i < len; ++i) {
      callbacks[i].apply(this, args);
    }
  }

  return this;
};

/**
 * Return array of callbacks for `event`.
 *
 * @param {String} event
 * @return {Array}
 * @api public
 */

Emitter.prototype.listeners = function(event){
  this._callbacks = this._callbacks || {};
  return this._callbacks[event] || [];
};

/**
 * Check if this emitter has `event` handlers.
 *
 * @param {String} event
 * @return {Boolean}
 * @api public
 */

Emitter.prototype.hasListeners = function(event){
  return !! this.listeners(event).length;
};

},{"indexof":24}],17:[function(_dereq_,module,exports){
(function (global){
/**
 * Module dependencies.
 */

var keys = _dereq_('./keys');
var sliceBuffer = _dereq_('arraybuffer.slice');
var base64encoder = _dereq_('base64-arraybuffer');
var after = _dereq_('after');

/**
 * Check if we are running an android browser. That requires us to use
 * ArrayBuffer with polling transports...
 *
 * http://ghinda.net/jpeg-blob-ajax-android/
 */

var isAndroid = navigator.userAgent.match(/Android/i);

/**
 * Current protocol version.
 */

exports.protocol = 2;

/**
 * Packet types.
 */

var packets = exports.packets = {
    open:     0    // non-ws
  , close:    1    // non-ws
  , ping:     2
  , pong:     3
  , message:  4
  , upgrade:  5
  , noop:     6
};

var packetslist = keys(packets);

/**
 * Premade error packet.
 */

var err = { type: 'error', data: 'parser error' };

/**
 * Create a blob api even for blob builder when vendor prefixes exist
 */

var Blob = _dereq_('blob');

/**
 * Encodes a packet.
 *
 *     <packet type id> [ <data> ]
 *
 * Example:
 *
 *     5hello world
 *     3
 *     4
 *
 * Binary is encoded in an identical principle
 *
 * @api private
 */

exports.encodePacket = function (packet, supportsBinary, callback) {
  if (typeof supportsBinary == 'function') {
    callback = supportsBinary;
    supportsBinary = false;
  }

  var data = (packet.data === undefined)
    ? undefined
    : packet.data.buffer || packet.data;

  if (global.ArrayBuffer && data instanceof ArrayBuffer) {
    return encodeArrayBuffer(packet, supportsBinary, callback);
  } else if (Blob && data instanceof global.Blob) {
    return encodeBlob(packet, supportsBinary, callback);
  }

  // Sending data as a utf-8 string
  var encoded = packets[packet.type];

  // data fragment is optional
  if (undefined !== packet.data) {
    encoded += String(packet.data);
  }

  return callback('' + encoded);

};

/**
 * Encode packet helpers for binary types
 */

function encodeArrayBuffer(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  var data = packet.data;
  var contentArray = new Uint8Array(data);
  var resultBuffer = new Uint8Array(1 + data.byteLength);

  resultBuffer[0] = packets[packet.type];
  for (var i = 0; i < contentArray.length; i++) {
    resultBuffer[i+1] = contentArray[i];
  }

  return callback(resultBuffer.buffer);
}

function encodeBlobAsArrayBuffer(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  var fr = new FileReader();
  fr.onload = function() {
    packet.data = fr.result;
    exports.encodePacket(packet, supportsBinary, callback);
  };
  return fr.readAsArrayBuffer(packet.data);
}

function encodeBlob(packet, supportsBinary, callback) {
  if (!supportsBinary) {
    return exports.encodeBase64Packet(packet, callback);
  }

  if (isAndroid) {
    return encodeBlobAsArrayBuffer(packet, supportsBinary, callback);
  }

  var length = new Uint8Array(1);
  length[0] = packets[packet.type];
  var blob = new Blob([length.buffer, packet.data]);

  return callback(blob);
}

/**
 * Encodes a packet with binary data in a base64 string
 *
 * @param {Object} packet, has `type` and `data`
 * @return {String} base64 encoded message
 */

exports.encodeBase64Packet = function(packet, callback) {
  var message = 'b' + exports.packets[packet.type];
  if (Blob && packet.data instanceof Blob) {
    var fr = new FileReader();
    fr.onload = function() {
      var b64 = fr.result.split(',')[1];
      callback(message + b64);
    };
    return fr.readAsDataURL(packet.data);
  }

  var b64data;
  try {
    b64data = String.fromCharCode.apply(null, new Uint8Array(packet.data));
  } catch (e) {
    // iPhone Safari doesn't let you apply with typed arrays
    var typed = new Uint8Array(packet.data);
    var basic = new Array(typed.length);
    for (var i = 0; i < typed.length; i++) {
      basic[i] = typed[i];
    }
    b64data = String.fromCharCode.apply(null, basic);
  }
  message += global.btoa(b64data);
  return callback(message);
};

/**
 * Decodes a packet. Changes format to Blob if requested.
 *
 * @return {Object} with `type` and `data` (if any)
 * @api private
 */

exports.decodePacket = function (data, binaryType) {
  // String data
  if (typeof data == 'string' || data === undefined) {
    if (data.charAt(0) == 'b') {
      return exports.decodeBase64Packet(data.substr(1), binaryType);
    }

    var type = data.charAt(0);

    if (Number(type) != type || !packetslist[type]) {
      return err;
    }

    if (data.length > 1) {
      return { type: packetslist[type], data: data.substring(1) };
    } else {
      return { type: packetslist[type] };
    }
  }

  var asArray = new Uint8Array(data);
  var type = asArray[0];
  var rest = sliceBuffer(data, 1);
  if (Blob && binaryType === 'blob') {
    rest = new Blob([rest]);
  }
  return { type: packetslist[type], data: rest };
};

/**
 * Decodes a packet encoded in a base64 string
 *
 * @param {String} base64 encoded message
 * @return {Object} with `type` and `data` (if any)
 */

exports.decodeBase64Packet = function(msg, binaryType) {
  var type = packetslist[msg.charAt(0)];
  if (!global.ArrayBuffer) {
    return { type: type, data: { base64: true, data: msg.substr(1) } };
  }

  var data = base64encoder.decode(msg.substr(1));

  if (binaryType === 'blob' && Blob) {
    data = new Blob([data]);
  }

  return { type: type, data: data };
};

/**
 * Encodes multiple messages (payload).
 *
 *     <length>:data
 *
 * Example:
 *
 *     11:hello world2:hi
 *
 * If any contents are binary, they will be encoded as base64 strings. Base64
 * encoded strings are marked with a b before the length specifier
 *
 * @param {Array} packets
 * @api private
 */

exports.encodePayload = function (packets, supportsBinary, callback) {
  if (typeof supportsBinary == 'function') {
    callback = supportsBinary;
    supportsBinary = null;
  }

  if (supportsBinary) {
    if (Blob && !isAndroid) {
      return exports.encodePayloadAsBlob(packets, callback);
    }

    return exports.encodePayloadAsArrayBuffer(packets, callback);
  }

  if (!packets.length) {
    return callback('0:');
  }

  function setLengthHeader(message) {
    return message.length + ':' + message;
  }

  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, supportsBinary, function(message) {
      doneCallback(null, setLengthHeader(message));
    });
  }

  map(packets, encodeOne, function(err, results) {
    return callback(results.join(''));
  });
};

/**
 * Async array map using after
 */

function map(ary, each, done) {
  var result = new Array(ary.length);
  var next = after(ary.length, done);

  var eachWithIndex = function(i, el, cb) {
    each(el, function(error, msg) {
      result[i] = msg;
      cb(error, result);
    });
  };

  for (var i = 0; i < ary.length; i++) {
    eachWithIndex(i, ary[i], next);
  }
}

/*
 * Decodes data when a payload is maybe expected. Possible binary contents are
 * decoded from their base64 representation
 *
 * @param {String} data, callback method
 * @api public
 */

exports.decodePayload = function (data, binaryType, callback) {
  if (typeof data != 'string') {
    return exports.decodePayloadAsBinary(data, binaryType, callback);
  }

  if (typeof binaryType === 'function') {
    callback = binaryType;
    binaryType = null;
  }

  var packet;
  if (data == '') {
    // parser error - ignoring payload
    return callback(err, 0, 1);
  }

  var length = ''
    , n, msg;

  for (var i = 0, l = data.length; i < l; i++) {
    var chr = data.charAt(i);

    if (':' != chr) {
      length += chr;
    } else {
      if ('' == length || (length != (n = Number(length)))) {
        // parser error - ignoring payload
        return callback(err, 0, 1);
      }

      msg = data.substr(i + 1, n);

      if (length != msg.length) {
        // parser error - ignoring payload
        return callback(err, 0, 1);
      }

      if (msg.length) {
        packet = exports.decodePacket(msg, binaryType);

        if (err.type == packet.type && err.data == packet.data) {
          // parser error in individual packet - ignoring payload
          return callback(err, 0, 1);
        }

        var ret = callback(packet, i + n, l);
        if (false === ret) return;
      }

      // advance cursor
      i += n;
      length = '';
    }
  }

  if (length != '') {
    // parser error - ignoring payload
    return callback(err, 0, 1);
  }

};

/**
 * Encodes multiple messages (payload) as binary.
 *
 * <1 = binary, 0 = string><number from 0-9><number from 0-9>[...]<number
 * 255><data>
 *
 * Example:
 * 1 3 255 1 2 3, if the binary contents are interpreted as 8 bit integers
 *
 * @param {Array} packets
 * @return {ArrayBuffer} encoded payload
 * @api private
 */

exports.encodePayloadAsArrayBuffer = function(packets, callback) {
  if (!packets.length) {
    return callback(new ArrayBuffer(0));
  }

  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, true, function(data) {
      return doneCallback(null, data);
    });
  }

  map(packets, encodeOne, function(err, encodedPackets) {
    var totalLength = encodedPackets.reduce(function(acc, p) {
      var len;
      if (typeof p === 'string'){
        len = p.length;
      } else {
        len = p.byteLength;
      }
      return acc + len.toString().length + len + 2; // string/binary identifier + separator = 2
    }, 0);

    var resultArray = new Uint8Array(totalLength);

    var bufferIndex = 0;
    encodedPackets.forEach(function(p) {
      var isString = typeof p === 'string';
      var ab = p;
      if (isString) {
        var view = new Uint8Array(p.length);
        for (var i = 0; i < p.length; i++) {
          view[i] = p.charCodeAt(i);
        }
        ab = view.buffer;
      }

      if (isString) { // not true binary
        resultArray[bufferIndex++] = 0;
      } else { // true binary
        resultArray[bufferIndex++] = 1;
      }

      var lenStr = ab.byteLength.toString();
      for (var i = 0; i < lenStr.length; i++) {
        resultArray[bufferIndex++] = parseInt(lenStr[i]);
      }
      resultArray[bufferIndex++] = 255;

      var view = new Uint8Array(ab);
      for (var i = 0; i < view.length; i++) {
        resultArray[bufferIndex++] = view[i];
      }
    });

    return callback(resultArray.buffer);
  });
};

/**
 * Encode as Blob
 */

exports.encodePayloadAsBlob = function(packets, callback) {
  function encodeOne(packet, doneCallback) {
    exports.encodePacket(packet, true, function(encoded) {
      var binaryIdentifier = new Uint8Array(1);
      binaryIdentifier[0] = 1;
      if (typeof encoded === 'string') {
        var view = new Uint8Array(encoded.length);
        for (var i = 0; i < encoded.length; i++) {
          view[i] = encoded.charCodeAt(i);
        }
        encoded = view.buffer;
        binaryIdentifier[0] = 0;
      }

      var len = (encoded instanceof ArrayBuffer)
        ? encoded.byteLength
        : encoded.size;

      var lenStr = len.toString();
      var lengthAry = new Uint8Array(lenStr.length + 1);
      for (var i = 0; i < lenStr.length; i++) {
        lengthAry[i] = parseInt(lenStr[i]);
      }
      lengthAry[lenStr.length] = 255;

      if (Blob) {
        var blob = new Blob([binaryIdentifier.buffer, lengthAry.buffer, encoded]);
        doneCallback(null, blob);
      }
    });
  }

  map(packets, encodeOne, function(err, results) {
    return callback(new Blob(results));
  });
};

/*
 * Decodes data when a payload is maybe expected. Strings are decoded by
 * interpreting each byte as a key code for entries marked to start with 0. See
 * description of encodePayloadAsBinary
 *
 * @param {ArrayBuffer} data, callback method
 * @api public
 */

exports.decodePayloadAsBinary = function (data, binaryType, callback) {
  if (typeof binaryType === 'function') {
    callback = binaryType;
    binaryType = null;
  }

  var bufferTail = data;
  var buffers = [];

  while (bufferTail.byteLength > 0) {
    var tailArray = new Uint8Array(bufferTail);
    var isString = tailArray[0] === 0;
    var msgLength = '';
    for (var i = 1; ; i++) {
      if (tailArray[i] == 255) break;
      msgLength += tailArray[i];
    }
    bufferTail = sliceBuffer(bufferTail, 2 + msgLength.length);
    msgLength = parseInt(msgLength);

    var msg = sliceBuffer(bufferTail, 0, msgLength);
    if (isString) {
      try {
        msg = String.fromCharCode.apply(null, new Uint8Array(msg));
      } catch (e) {
        // iPhone Safari doesn't let you apply to typed arrays
        var typed = new Uint8Array(msg);
        var basic = new Array(typed.length);
        for (var i = 0; i < typed.length; i++) {
          basic[i] = typed[i];
        }
        msg = String.fromCharCode.apply(null, basic);
      }
    }
    buffers.push(msg);
    bufferTail = sliceBuffer(bufferTail, msgLength);
  }

  var total = buffers.length;
  buffers.forEach(function(buffer, i) {
    callback(exports.decodePacket(buffer, binaryType), i, total);
  });
};

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./keys":18,"after":19,"arraybuffer.slice":20,"base64-arraybuffer":21,"blob":14}],18:[function(_dereq_,module,exports){

/**
 * Gets the keys for an object.
 *
 * @return {Array} keys
 * @api private
 */

module.exports = Object.keys || function keys (obj){
  var arr = [];
  var has = Object.prototype.hasOwnProperty;

  for (var i in obj) {
    if (has.call(obj, i)) {
      arr.push(i);
    }
  }
  return arr;
};

},{}],19:[function(_dereq_,module,exports){
module.exports = after

function after(count, callback, err_cb) {
    var bail = false
    err_cb = err_cb || noop
    proxy.count = count

    return (count === 0) ? callback() : proxy

    function proxy(err, result) {
        if (proxy.count <= 0) {
            throw new Error('after called too many times')
        }
        --proxy.count

        // after first error, rest are passed to err_cb
        if (err) {
            bail = true
            callback(err)
            // future error callbacks will go to error handler
            callback = err_cb
        } else if (proxy.count === 0 && !bail) {
            callback(null, result)
        }
    }
}

function noop() {}

},{}],20:[function(_dereq_,module,exports){
/**
 * An abstraction for slicing an arraybuffer even when
 * ArrayBuffer.prototype.slice is not supported
 *
 * @api public
 */

module.exports = function(arraybuffer, start, end) {
  var bytes = arraybuffer.byteLength;
  start = start || 0;
  end = end || bytes;

  if (arraybuffer.slice) { return arraybuffer.slice(start, end); }

  if (start < 0) { start += bytes; }
  if (end < 0) { end += bytes; }
  if (end > bytes) { end = bytes; }

  if (start >= bytes || start >= end || bytes === 0) {
    return new ArrayBuffer(0);
  }

  var abv = new Uint8Array(arraybuffer);
  var result = new Uint8Array(end - start);
  for (var i = start, ii = 0; i < end; i++, ii++) {
    result[ii] = abv[i];
  }
  return result.buffer;
};

},{}],21:[function(_dereq_,module,exports){
/*
 * base64-arraybuffer
 * https://github.com/niklasvh/base64-arraybuffer
 *
 * Copyright (c) 2012 Niklas von Hertzen
 * Licensed under the MIT license.
 */
(function(chars){
  "use strict";

  exports.encode = function(arraybuffer) {
    var bytes = new Uint8Array(arraybuffer),
    i, len = bytes.buffer.byteLength, base64 = "";

    for (i = 0; i < len; i+=3) {
      base64 += chars[bytes.buffer[i] >> 2];
      base64 += chars[((bytes.buffer[i] & 3) << 4) | (bytes.buffer[i + 1] >> 4)];
      base64 += chars[((bytes.buffer[i + 1] & 15) << 2) | (bytes.buffer[i + 2] >> 6)];
      base64 += chars[bytes.buffer[i + 2] & 63];
    }

    if ((len % 3) === 2) {
      base64 = base64.substring(0, base64.length - 1) + "=";
    } else if (len % 3 === 1) {
      base64 = base64.substring(0, base64.length - 2) + "==";
    }

    return base64;
  };

  exports.decode =  function(base64) {
    var bufferLength = base64.length * 0.75,
    len = base64.length, i, p = 0,
    encoded1, encoded2, encoded3, encoded4;

    if (base64[base64.length - 1] === "=") {
      bufferLength--;
      if (base64[base64.length - 2] === "=") {
        bufferLength--;
      }
    }

    var arraybuffer = new ArrayBuffer(bufferLength),
    bytes = new Uint8Array(arraybuffer);

    for (i = 0; i < len; i+=4) {
      encoded1 = chars.indexOf(base64[i]);
      encoded2 = chars.indexOf(base64[i+1]);
      encoded3 = chars.indexOf(base64[i+2]);
      encoded4 = chars.indexOf(base64[i+3]);

      bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
      bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
      bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
    }

    return arraybuffer;
  };
})("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
},{}],22:[function(_dereq_,module,exports){

/**
 * Module dependencies.
 */

var global = _dereq_('global');

/**
 * Module exports.
 *
 * Logic borrowed from Modernizr:
 *
 *   - https://github.com/Modernizr/Modernizr/blob/master/feature-detects/cors.js
 */

try {
  module.exports = 'XMLHttpRequest' in global &&
    'withCredentials' in new global.XMLHttpRequest();
} catch (err) {
  // if XMLHttp support is disabled in IE then it will throw
  // when trying to create
  module.exports = false;
}

},{"global":23}],23:[function(_dereq_,module,exports){

/**
 * Returns `this`. Execute this without a "context" (i.e. without it being
 * attached to an object of the left-hand side), and `this` points to the
 * "global" scope of the current JS execution.
 */

module.exports = (function () { return this; })();

},{}],24:[function(_dereq_,module,exports){

var indexOf = [].indexOf;

module.exports = function(arr, obj){
  if (indexOf) return arr.indexOf(obj);
  for (var i = 0; i < arr.length; ++i) {
    if (arr[i] === obj) return i;
  }
  return -1;
};
},{}],25:[function(_dereq_,module,exports){
(function (global){
/**
 * JSON parse.
 *
 * @see Based on jQuery#parseJSON (MIT) and JSON2
 * @api private
 */

var rvalidchars = /^[\],:{}\s]*$/;
var rvalidescape = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g;
var rvalidtokens = /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;
var rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g;
var rtrimLeft = /^\s+/;
var rtrimRight = /\s+$/;

module.exports = function parsejson(data) {
  if ('string' != typeof data || !data) {
    return null;
  }

  data = data.replace(rtrimLeft, '').replace(rtrimRight, '');

  // Attempt to parse using the native JSON parser first
  if (global.JSON && JSON.parse) {
    return JSON.parse(data);
  }

  if (rvalidchars.test(data.replace(rvalidescape, '@')
      .replace(rvalidtokens, ']')
      .replace(rvalidbraces, ''))) {
    return (new Function('return ' + data))();
  }
};
}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],26:[function(_dereq_,module,exports){
/**
 * Parses an URI
 *
 * @author Steven Levithan <stevenlevithan.com> (MIT license)
 * @api private
 */

var re = /^(?:(?![^:@]+:[^:@\/]*@)(http|https|ws|wss):\/\/)?((?:(([^:@]*)(?::([^:@]*))?)?@)?((?:[a-f0-9]{0,4}:){2,7}[a-f0-9]{0,4}|[^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/;

var parts = [
    'source', 'protocol', 'authority', 'userInfo', 'user', 'password', 'host'
  , 'port', 'relative', 'path', 'directory', 'file', 'query', 'anchor'
];

module.exports = function parseuri(str) {
  var m = re.exec(str || '')
    , uri = {}
    , i = 14;

  while (i--) {
    uri[parts[i]] = m[i] || '';
  }

  return uri;
};

},{}],27:[function(_dereq_,module,exports){

/**
 * Module dependencies.
 */

var global = (function() { return this; })();

/**
 * WebSocket constructor.
 */

var WebSocket = global.WebSocket || global.MozWebSocket;

/**
 * Module exports.
 */

module.exports = WebSocket ? ws : null;

/**
 * WebSocket constructor.
 *
 * The third `opts` options object gets ignored in web browsers, since it's
 * non-standard, and throws a TypeError if passed to the constructor.
 * See: https://github.com/einaros/ws/issues/227
 *
 * @param {String} uri
 * @param {Array} protocols (optional)
 * @param {Object) opts (optional)
 * @api public
 */

function ws(uri, protocols, opts) {
  var instance;
  if (protocols) {
    instance = new WebSocket(uri, protocols);
  } else {
    instance = new WebSocket(uri);
  }
  return instance;
}

if (WebSocket) ws.prototype = WebSocket.prototype;

},{}]},{},[1])
(1)
});

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
  </head>
  <body>
    <script src="/engine.io.js"></script>
    <script src="/client.js"></script>
  </body>
</html>

package.json

{
  "name": "xhr-polling",
  "version": "0.0.0",
  "description": "xhr polling issue",
  "main": "server.js",
  "dependencies": {
    "engine.io": "^1.0.5"
  },
  "scripts": {
    "start": "node server.js"
  },
  "author": "",
  "license": "MIT"
}

server.js

var fs = require('fs')
  , http = require('http');

var server = http.createServer(function (req, res) {
  if (req.url === '/client.js') {
    res.setHeader('Content-Type', 'application/javascript');
    fs.createReadStream(__dirname + '/client.js').pipe(res);
    return;
  }
  if (req.url === '/engine.io.js') {
    res.setHeader('Content-Type', 'application/javascript');
    fs.createReadStream(__dirname + '/engine.io.js').pipe(res);
    return;
  }
  res.setHeader('Content-Type', 'text/html');
  fs.createReadStream(__dirname + '/index.html').pipe(res);
});

var io = require('engine.io').attach(server);

io.on('connection', function (socket) {
  socket.send('bar');
});

server.listen(3000, function () {
  console.log('listening on localhost:3000');
});