Ultimate ajax resource

[webmidas]

Hello friend,
I am seeing lot of people are crazy about Ajax.SO,finally i decided to learn ajax.But since i donot have overall clue about ajax.I serched google and obvoiusly i found lots of ajax resources.But the problem is that i am totally newbie for ajax and so i need a resouce which could teach me everything to get at least intermediate knowledge of ajax.
I am a php developer.
Please tell me some really nice resources for Ajax for php developer.
site or even ebook will work.
thanks

[Twey]

AJAX isn't a specific technology, it's a design methodology that makes use of a few existing technologies. If you know PHP and Javascript, you already know AJAX. However, AJAX isn't always the best way to go: a lot of the time, JSON is a lot less awkward to work with than XML. Whatever you choose, remember that non-JS users must be able to access your site too! It's all too easy to forget accessibility when working extensively with Javascript.