Ajax question

[qweasdzxc]

I am a little confused about how ajax works. I understand the javascript client-side making server-requests..but where exactly does server-side code (like python or perl or php) come into play in this model? It seems to me that javascript can take care of everything client-side.

[Alan]

AJAX is used to silently (without being noticed) load new data from the server. It is a combination of both a client side and a server side operation. JavaScript cannot by itself operate beyond the browser, it requires help on the server side front. What happens is that the client (JavaScript) requests information from the server. This is where the server side scripting language comes in. PHP/Perl/Python/Java Servlets/ASP.net (to just name a few) will fetch the data that is needed and return it to the client, where it will be displayed without the need for a page reload.