The World Wide Web Consortium (W3C) has approved Document Object
Model (DOM) Level 3 Core and Load and Save specifications as official W3C recommendations, a move that stamps out vestiges of the browser wars and makes way for Web interoperability.
The specification means that developers will be able to deploy scripting for programs that can interoperate with different browsers.
W3C’s DOM is an Application Programming Interface (API) standard that deals with the structure of documents. The purpose of DOM is to make it possible for developers to easily access components and enable applications that are compatible across all browsers, servers and platforms.
“The new set of specifications achieves most of the requirements we had back in 1997, before XML
The history of W3C’s DOM effort began during the browser wars of the late nineties between Microsoft’s IE and Netscape’s Navigator, in an effort to address browser incompatibility. DOM Level 3 is the culmination of a multilevel process that originally began in August 1997 with Netscape 3.0 and Microsoft Internet Explorer 3.0 as baselines. DOM Level 1, which provides support for XML 1.0 and HTML 4.0, was completed in October of 1998.
DOM Level 2 Core was completed in November 2000 though the HTML
component of the specification did not become a recommendation until January 2003. DOM Level 2 is well known in the Web developer community as the specification that, among other notable items, defines the standard for Cascading Style Sheets.
“DOM Level 1 is widely deployed in Web user agents. DOM Level 2 is
slower than expected on that side, especially around HTML, and one has to expect that DOM Level 3 will take some significant time before being deployed in Web user agents,” Le Hegaret told internetnews.com. “However, all SVG user agents that implement scripting use DOM level 2 Core and XML.”
W3C’s DOM Activity Lead went on to explain that DOM Levels 1 and 2 have been widely deployed in other Web applications, such as the Java platform, which adopted Level 2 early on and is expected to upgrade to Level 3 as soon as possible. “Lots of languages provide DOM support
nowadays,” Le Hegaret added.
“The DOM Level 3 specification covers a lot of ground. Only parts of the spec are relevant to browser technologies,” Brendan Eich, chief architect at the Mozilla Foundation, told internetnews.com . “Among the relevant parts, Load and Save will help us gain ground on Web services capabilities that Mozilla wants to build into the browser, and we’re actively looking into implementing this Load and Save part of the spec into Mozilla.”
The DOM Level 3 Load and Save Recommendation, according to Le Hegaret, provides an interoperable way to load an XML document into a
DOM tree in memory, or save the DOM tree in memory into an XML document.
Le Hegaret said he expects the transition between DOM Level 2 and DOM Level 3 for developers will be smooth, now that the W3C has signaled the latest recommendation is stable for adoption by developers.
“As the needs are growing, the developers will require DOM Level 3
support in order to develop XML applications,” he said. “Given the attractive aspects of DOM Level 3 in terms of simplifying their lives, the developers will start using it pretty soon.”
Web Services are also a large component of the new DOM recommendation. DOM Level 3 extends XML support to version 1.1 and other components of the XML Information Set specification bringing DOM in line with XML Schema 1.0 and SOAP 1.2 W3C Recommendations. The new recommendation also makes full use of XML namespaces, which enables easier manipulation of WSDL
DOM Level 3 is the final evolution of the DOM process that began seven years ago at the W3C. Le Hegaret said now that the DOM Working Group has completed its original mission, other groups will continue to extend the DOM platform for more specific use, such as the SVG Working Group.
“While we do now have an appropriate representation for XML Documents in memory, challenges remain to be addressed. The future W3C Workshop on Web Applications and Compound Documents will certainly help focusing on them.”
