XML Spec May Transform The Web

By Karen Rodriguez

A little-known markup language promises to propel the World Wide Web from its inert form to a more intelligent and interactive service.

The Extensible Markup Language, or XML, is expected to enable Web personalization, improved search services, the push of information to desktops and more advanced processing of complex data on client systems.

Now available as a first draft specification, XML was created by the World Wide Web Consortium, or W3C (www.w3c.org), to augment the HyperText Markup Language, or HTML, standard. HTML is a significant delivery and presentation mechanism for the Web, but many users are currently pushing the language's feature set.

"HTML has been tremendously successful, but a lot of people, particularly those in the professional publishing market, find it is limiting. Everyone [who's] doing anything ambitious on the Web is screaming for extensions to HTML," says Tim Bray, co-author of the XML specification and principal of Textuality (www.textuality.com), a consulting practice based in Vancouver, British Columbia.

Web publishers have been looking for smarter client and server software with which to represent and dynamically generate data stored in relational, object and document databases.

"HTML is good for presentation; but it does not support smart downstream processing," Bray says in reference to client-side information processing.

For example, as a generalized language, HTML is ill-suited for publishing auto industry technical manuals, which include specific part numbers and descriptions of parts assembly.

HTML also doesn't allow Web-based human-resource applications to represent new data types, such as date of hire and date of birth.

On the other hand, XML offers application-specific tags that can help organize and define content.

According to analysts at CAP Ventures, a consulting and research firm that focuses on document technology, there are three problems with HTML: There are several different versions of HTML that are incompatible; the language is limited and does not let users create attractive Web documents; and users are unable to extend HTML to add custom tags.

"XML attempts to fix two of those problems: It solves the version problem, but more importantly, it solves the user extensibility problem," says Frank Gilbane, director of the Norwell, Mass., consultancy. "When people try to build large document Web systems with HTML; they can't do it. XML provides just enough capability to allow people to create their own extensions without wreaking havoc, which happens now [in HTML]."

Microsoft Corp. (wwwmicrosoft.com) and Netscape Communications Corp. (www.netscape.com) both say they will support XML in their respective browsers.

Netscape says support for XML will not be available in the upcoming Communicator browser suite, due this summer, but the language will be implemented in the future.

XML "looks like it is becoming an important standard; clearly, it is a great way to augment HTML with structured data," says Eckart Walther, Netscape's product manager for Communicator.

However, because the XML spec is still in the proposal stage and not expected to be complete until the end of the year, Walther says, it is too early to project how the company will support the language other than in the browser.

Microsoft is a bit more definite. The company says it will include an XML extension in its upcoming Internet Explorer 4.0, or IE 4.0, browser suite, due this summer.

Microsoft will use XML to define how information will be pushed to the desktop using the Channel Definition Format, or CDF, a Microsoft standard for delivering data to its browser.

Microsoft and Intuit Inc. (www.intuit.com), a maker of personal finance software, are using XML to define a specific format in Microsoft Money and Intuit's Quicken packages that let users move money between different accounts.

With XML, the companies are able to create specific tags for the name of the withdrawal bank, the bank's address, phone number and transaction.

"We think XML is of epic importance," says Thomas Reardon, group program manager in the Internet client and collaboration division at Microsoft. "We'll have support for XML in several apps, including CDF, and that's important, because rather than create scripts and new APIs [Application Program Interfaces] to identify a channel, we can do it with simple data descriptions in XML."

XML: The Next Generation

Next-generation HyperText Markup Language, or HTML, is taking shape. The World Wide Web Consortium, or W3C, has defined Extensible Markup Language, or XML, to further improve document publishing on the Web.

What is XML?

XML is a system for defining, validating and sharing document formats. It allows Web users to create, manage and access dynamic, personalized and customized content on the Web.

How does it differ from HTML?

HTML is a good document delivery mechanism but is unable to support structured data such as database tables in Web pages. With XML, businesses can distribute structured databases that users can manipulate at will.

How does it differ from Standard Generalized Markup Language, or SGML?

XML is a subset of SGML but is much easier to use. XML can be used as the network delivery mechanism for SGML documents.