http://www.adaptivepath.com/publications/essays/archives/000385.php is an pretty informative article on how Ajax works.
- Zarutian 7. august 2005
DKF: It's actually a pseudo-framework. The AJAX model is supported by many different frameworks, and as long as your server can talk XML (typically a trivial task!) you're at least potentially in the game. The real complexity is that you have to deal with many different and inconsistent browsers (especially IE6...)
To add AJAX functionalities in your TCL web scripts:
It would be nice to be able to demonstrate AJAX-like behavior in Tcl.
schlenk 26 Sep 2005 - With the Tcl Plugin you don't need all the XML mumbo jumbo, just open a socket back to the original server or do some http requests via the http package to get the dynamic info you want.
LES same day: open a socket and leave it open for as long as the browser window is open? For each visitor? Then I suppose a few thousand open sockets could accumulate in just a few minutes if the site is popular enough. I imagine the impact on the server's performance.
schlenk it really depends. Having a socket open would mean the server can push information to the client. Doing HTTP means polling by the client. So just open sockets do no real harm (some small amount of memory), but the limited amount of ports will eventuell hit). As there is no simple way to increase the number of available ports but it is simpler to increase the computing power of the server so it can serve many more empty polling requests its probably the way to go. Especially as most AJAX apps are inherently: user sends data to server and gets update and not something like stock tickers etc. where the server would like to push data. Its more an RPC thing.
Also: google for the terms "reverse Ajax" and "long polling" for ways to overcome latency and overhead in push scenarios -jcw