May 19, 1997,
XML Is The Future Of HTML
By Jason Levitt
Sick of HTML? You're not the only one. Hypertext markup language, crafted a few years ago to display simple, formatted text and pictures on the Internet, is becoming a hacked-up mess.
HTML still doesn't solve many application-development problems or offer straightforward methods of implementing Web solutions. New extensions such as Dynamic HTML and Cascading Style Sheets are creating a richer Internet landscape, but as a whole they just seem like more boards nailed on to a sagging wooden shack.
What's needed is a markup language that can be extended without needing new standards. XML (eXtensible markup language), a subset of SGML (standard general markup language) and an emerging World Wide Web Consortium standard, is an extensible markup language that offers the best alternative for Internet applications developers.
XML offers all the power of Dynamic HTML, Style Sheets, and other HTML extensions within the confines of an extensible framework. Unlike HTML, XML documents are specified in two parts. One is the XML document itself, which may look like an HTML document except that it will probably have a lot of new tags. The other part is a Document Type Definition that explains what the new tags mean and how they should be interpreted. The separation of the DTD from the document's contents lets Web developers extend the language simply by creating new DTD files.
What might a simple XML file look like? Here's an example that could be used to display an InformationWeek Online NewsFlash headline:
Steve Jobs Lands On The Moon
The first line says that this is an XML 1.0 document. The second line defines the document name, "iweekflash," and the location of the DTD, which is in the file named flash.dtd. This file describes what the tagmeans and how it should be interpreted. In this case, the words inside the tag are the headline for a hot news item that might appear formatted on the InformationWeek's home page.
This example barely scratches the surface of XML's power. XML frees developers from the restrictions of HTML. It will be especially useful for applications that must offer users many structured choices, such as database front ends, online ticketing, and catalog shopping. The current World Wide Web Consortium draft standard for XML can be found at www.textuality.com/sgml-erb/WD-xml.html.
-Jason Levitt can be reached at firstname.lastname@example.org
You can read his Internet Zone column on InformationWeek Online at techweb.cmp.com/iw/author/internet.htm
Copyright ® 1997 CMP Media Inc.