Basic knowledge - Ajax and XML

Basic knowledge - Ajax and XML

Hi @ all.

At first: I'm using jQuery and I love it. The handling is beautiful and there are a lot of situations you can use jQuery for problems, for code-optimizing and and and. .. but why do I say this things to you ... You know it already ;D

To the cause of my topic:
I use the ajax functions too (which works fine) and often I read about XML in coherence with ajax.
My question is:

Where is the XML :D
when I make an ajax-request i type in the destination-url, sometimes paramaters to send ('data .....') and the other basicinformations ( you know).

The result which I read is for usual html-code which I place into my current site. ( -> callback function success .....)

But where are the XML-Data? is it only an intern struct or ...... ?
Also I tried the JSON-function too and there the response is a json-struct.

I hope you can understand my question (My english is not the best :-/ But I am too stupid to speak my mother-language, too ;-D )

Thank you in ahead for your informations.
sham.