Function onerror

public/javascripts/socket.io.js:4163–4172

(err)

	  // Handle any error that happens while probing
	  function onerror (err) {
	    var error = new Error('probe error: ' + err);
	    error.transport = transport.name;

	    freezeTransport();

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

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

	  function onTransportClose () {
	    onerror('transport closed');