Section: Insights & Incites
XML Will Do For Web Apps What HTML Did For Web Publishing
By Richard Karpinski
If key Web vendors have their way, the Extensible Markup Language will soon be like "It's A Wonderful Life" on Christmas Eve: playing everywhere and running seemingly nonstop.
XML has another thing in common with the holiday season-it can mean vastly different things to different people.
Yet as developments this month have shown, including the posting of the core specification for a World Wide Web Consortium member vote, XML is here to stay. And like a child's countdown to Dec. 25, it grows in importance every day.
Doubt it? Count the ways XML will change the Web.
Let's start at the beginning. What exactly is XML? In short, it's a simplified, Webified version of the Standard Generalized Markup Language (SGML), which is an international standard used by companies and industries today to mark up large documents and make them easier to store, search and navigate.
XML is important in any number of ways. For starters, it complements the weaknesses of HTML, which already is stretched beyond its limits.
With XML, in comparison, application builders-and industries for that matter-can create sets of tags that define and describe their data much more accurately. For instance, in a commerce application it would be great to have tags for
Once data is described-that is, once meta-data, or data about data, is created-very powerful things occur.
Web designers can better store, manage and lay out Web documents. Even more important, application developers can take advantage of a simple, cross-platform, standards-based, client- and server-supported data exchange format that is infinitely flexible. Finally, users will benefit from more precise Web-searching applications that use XML to sift through the info-glut and more.
So where, precisely, will XML matter most? I'd wager its value as a document-centric language will come in second to its power as a data exchange format. HTML, and now Dynamic HTML, may have shortcomings, but for the Web-user interface they will remain king.
Indeed, just as HTML launched a million Web pages, XML will launch a like number of Web applications and transactions.
Let's come right out and say it: In the not-too-distant future, XML, coupled with DHTML-based scripting, will be the primary way most Web applications are built.
How will XML break out to the mainstream? Most likely, closed environments like intranets and extranets will use it first to streamline commerce and transaction apps.
Broad browser support will come next, probably by the middle of next year. Internet Explorer 4.0 has some XML support; Netscape is targeting its next release.
That's when things get really interesting. With XML universally supported in Web clients, and Web sites adding XML encoding to their documents, the Web moves to its next level: true networked, machine-to-machine communications.
The result: more finely tuned Web searching and indexing via XML-reading spiders; speedy real-time transactions driven by XML data exchange; buyer-driven Web agents that search for the best prices and deals; and much more.
Things like Java will continue to be important, in part because more programmatic XML-based Web pages will give Java applets and applications something meatier on which to chew. Jon Bosak, one of the pioneers in the XML movement, is a Sun employee who from the start saw XML and Java as deeply complementary.
But XML has its own advantages. Like HTML, it's simple, character-based and soon-to-be a W3C standard.
So pay heed to XML. Like George Bailey in "It's a Wonderful Life," the world (wide Web) is a better place for it having been born.
Richard Karpinski is an editor at large at InternetWeek.
Copyright (c) 1997 CMP Media Inc.
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