Web Design in a Nutshell

Chapter 25. Introduction to XML

XML (Extensible Markup Language) is a new standard that has recently been approved by the World Wide Web Consortium. It is a promising new customizable markup language that will allow for complex information transactions on the Internet. Many companies such as Microsoft and Netscape have developed or are developing XML technologies.

HTML is designed for content being sent to a browser, but isn’t good for sending content to other mediums like a printer or a ticker. XML allows developers to create a custom markup language specific to their needs.

Specially coded XML documents reside on a server and can be converted to HTML and read by browsers. Other clients (including future browsers that are XML-compliant) can access the XML documents directly and use the content for a variety of purposes.

Background

Although XML is a markup language like HTML, a common misconception is that XML is HTML on steroids. XML and HTML are related, but through a common parent, SGML, Standard General Markup Language. SGML is a meta-language—a comprehensive set of syntax rules for marking up documents and data. For information on SGML, including its history, see http://www.www.sil.org/sgml/, and specifically, http://www.sil.org/sgml/general.html.#hist.

When the creators of the Web needed a markup language that told browsers how to display web content, they used SGML guidelines to create HTML. HTML was designed specifically for displaying content in a browser, but isn’t good for ...