Extensible Markup Language, or XML, is currently the most promising language for storing and exchanging information on the World Wide Web. Although Hypertext Markup Language (HTML) is presently the most common language used to create Web pages, HTML has a limited capacity for storing information. In contrast, because XML allows you to create your own elements, attributes, and document structure, you can use it to describe virtually any kind of information—from a simple recipe to a complex database. And an XML document—in conjunction with a style sheet or a conventional HTML page— can be easily displayed in a Web browser. Because an XML document so effectively organizes and labels.
