Even if you're a newbie, you know that HTML stands for Hypertext Markup Language. Perhaps you've even used HTML to code a Web page. But now, there's a next-generation Web technology called Extensible Markup Language (or XML for short) that's causing programmers to sit up and cheer.

Developed by a Sun Microsystems engineer Jon Bosak, XML offers data portability and reusability across different platforms and devices. It is also flexible and extensible, allowing new tags to be added without breaking an existing document structure. Microsoft calls XML "the universal format for data on the Web."

XML can keep data separated from HTML, store data inside HTML documents, be used as a format to exchange information, and be used to store data in files or in databases.

XML can be used to mark up:

• An ordinary document.
• A structured record, such as an appointment record or purchase order.
• An object with data and methods, such as the persistent form of a Java object or ActiveX control.
• A data record, such as the result set of a query.
• Meta content about a Web site, such as Channel Definition Format.
• Graphical presentation, such as an application's user interface.
• Standard schema entities and types.
• All links between information and people on the Web.

Dealing with Data

Shelby Rogers, a producer at interactive agency iDev in Silver Spring, Maryland, started using XML recently for a client project. The project involved putting several complex technical publications (more than 500 pages each) online. Since these documents needed to be updated regularly, the client wanted a tool that would allow people to update whenever they wanted. That's where XML came in. Rogers and her team used Dynabase, a robust content management solution based on XML. "Wherever there is a page that displays information about a publication, or the publication itself, or an offer to subscribe to it, there is XML behind it. Basically, everything except the company information page and the copyright statement," she says.

According to Rogers, learning XML wasn't terribly difficult. She learned by reading books, taking classes and going to an XML conference. Even though it's not difficult to learn, "you need to be able to wrap your head around the data, not just the structure you want to present it in," she says.

"It's not just advanced HTML, it's far more powerful and complex. Call me an evangelist for saying this if you will, but when the standards are established, it will be a whole new way to deal with large amounts of data and should be approached with an understanding of its capabilities," says Rogers.