How does the live, real-time typing work in Google Wave?

Question

I\'m sure Wave doesn\'t poll the server every millisecond to find out if the other user has typed something... so how can I see what the other person is typing as they type? And

Answer 1

Server Push in GWT

Server push is the Wait, Respond, Close, Re-Open paradigm:

• Wait: When the GWT code makes a call to your server for some data that you don't have yet, freeze (wait)

• Respond: Once the requested data is
  available, respond with it

• Close: Then, close the connection.

• Re-Open: Once your GWT code receives the response, immediately open up a new connection to query for the next event.

Answer 2

Pure speculation but could it be using the Server Side DOM events from the HTML 5 spec?

Answer 3

Persistent HTTP, Comet

Keep your HTTP connection alive and send characters as they are typed

*Edit in 2014: also, take a look at WebSocket and HTTP/1.1 Upgrade header. Browsers started implementing this around 2010, so I'm adding this to original answer.