Alternative to survey. HTML Updates

Question

I am working on a collaborative website that I want to provide to users while they are browsing or editing data. Something similar to the way in StackOverflow, if you answer a question and a notification appears at the top, saying that there is a new response to the message.

I see how to do this using some kind of AJAX magic for polling, but I was wondering if there is a way to send a notification to the browser without using polling?

Thanks for any help / ideas :)

EDIT:

For those who wish, I went with SignalR https://github.com/SignalR/SignalR/wiki/Hubs

Answer 1

Either use a long poll to make it work in older browsers, or start reading on eventSource:

http://dev.w3.org/html5/eventsource/

Good article by Nicholas Zakas:

http://www.nczonline.net/blog/2010/10/19/introduction-to-server-sent-events/

Answer 2

Well, I'm starting to use Websockets (see some of my previous questions), and they are cool to use instead of ajax: -D

Answer 3

As a rule, no, but there are many methods that mimic this effect.

Look at the comet if you want to take a picture: http://en.wikipedia.org/wiki/Comet_ (programming)