web-based app: how to trigger popup on someone else's computer?

I have a web-based app where all subscribers are logged in to the site. When
Person A presses a button to notify Person B that someone is here to see
him, Person B gets a popup on his screen notifying that some is there. (like
instant messaging)

How can you program a popup screen to display on a remote user's screen with
a message written by Person A? (Both are logged in to the system).

Would you just poll every 15 seconds? That would create a lot of unnecessary
network traffic.

Any ideas?

Many thanks!

"TriAdmin" <lof@invalid.comwrites:
Polling is definitely the easiest way to go about it, though you may
want to search on Comet. Note that not everyone here is convinced its
problems are worth the gains. I'm currently working on a comet-like
system meself, and until that's been tried in the wild I'm leaning
towards "worth the trouble, but only for certain problems".

--
Joost Diepenmaat | blog: http://joost.zeekat.nl/ | work: http://zeekat.nl/

what is Comet?


"Joost Diepenmaat" <joost@zeekat.nlwrote in message
news:87skz364ts.fsf@zeekat.nl...

found it - many thanks Joost!


"Joost Diepenmaat" <joost@zeekat.nlwrote in message
news:87skz364ts.fsf@zeekat.nl...