Ajax

I'm used to Flash...and now feel curious about Ajax introduced in lass. I think I heard of it before, but don't really know it. It's 「Asynchronous JavaScript and XML」. It's for dynamic pages.
It seems there are so many things I need to know and to learn. I put hints here in case I want to know more later.

Ajax uses a combination of:

• XHTML (or HTML) and CSS for marking up and styling information.
• The DOM accessed with a client-side scripting language, especially ECMAScript implementations such as JavaScript and JScript, to dynamically display and interact with the information presented.
• The XMLHttpRequest object is used to exchange data asynchronously with the web server. In some Ajax frameworks and in certain situations, an IFrame object is used instead of the XMLHttpRequest object to exchange data with the web server, and in other implementations, dynamically added <script> tags may be used.
• XML is sometimes used as the format for transferring data between the server and client, although any format will work, including preformatted HTML, plain text and JSON. These files may be created dynamically by some form of server-side scripting.