Ajax XML and XHTML

[coffeecup]

Hello

I have worked my way through XHTML PHP CSS MySQL and now am getting into Javascript with the focas on using Ajax.

Yet, while looking over Ajax and see`ing XML here and there without any clarification of XML`s role in Ajax, while Ajax information is geared towards either HTMl or XML.

And seeing PHP in conjunction with Ajax with previous know how to, pointing to use XHTML with PHP and MySQL.

It is all becoming a swirling bi o mass of confusion.

 

So, a question to pose, would be: Do you know of any resource`s that show in text  definitive distinctions. And if the bowl of code soup using different code constructs languages are to be mixed like salad, what is the top secret splice O matic and how would that be declared in the DTD.

Any assistance ?

Thank you