Abstract: A first device, such as a PC, is enabled to receive messages from a second device, such as an application server, that does not know the address of the first device, by interaction with an intermediate man-in-the-middle (MITM) server. The first device obtains an ID, provides the ID to a human using the first device, and then the human provides the ID to the second device. The second device sends a message to the MITM server addressed to the ID. Meanwhile, the first device long polls the MITM server, and in response to one of the long polls, the MITM server sends the message from the second device to the first device. The first device is operating according to a script that was received from an external device, in response to a request for the script from the first device. The request for the script is embedded in a web page that the first device received; the script request may be launched automatically by the web page or in response to an action by the human.