Alternative to Polling. HTML Updates
Either use long polling for it to work in older browsers, or start reading up on eventSource:
http://dev.w3.org/html5/eventsource/
Nice article by Nicholas Zakas:
http://www.nczonline.net/blog/2010/10/19/introduction-to-server-sent-events/
Generally no, but there is a family of techniques that simulate such an effect.
Look into comet if you'd like to give it a shot: http://en.wikipedia.org/wiki/Comet_(programming)