[SOLVED] What is XML good for?

[phrozenflame]

I know everything in web design has a place. there is one language I was wondering about.
xhtml is to create the page.  Css is to style the page.  Javascript is to add some special functions, and unique actions, php is to dramatize, and make the page dynamic, sql(variations) are to database a website when needed.  and add database.  IN the general scope of things what would xml be used for.  What purposes does it serve, I know at w3 it states it works with the other langues, so I can use Xhtml, css, Php, Sql, javascript, and still have a fundamental purpose for xml to work with all of those, so what would that purpose be and what would be the reason for xml

[trq]

xml is a markup language the same as html except I believe html was designed to display data while xml was designed more to describe data.

You could almost think of xml as a database. It is a method of storing data with a description of what the data is. For instance, when you query a database for a users name, you know your going to get a users name back. You can do the same via xml by parsing the document and pulling out a users name. You can do this because xml describes its data. eg; A users name would be between tags such as <username> for example. You can't do this with html because a users name could be between any tag, and those tags do not describe the data they hold.

Where does xml belong? It is very usefull for transfering data from one application to another. eg; An rss feed, or even moving data from a php application into a flash interface. Now days allot of people are using it to transfer data from php backends to Javascript/HTML frontends (Ajax).

[phrozenflame]

Thanks