America Online's Netscape Communications division has long promised support for the standardized Document Object Model (DOM) in its upcoming version 5.0 of the Communicator browser. The World Wide Web Consortium (W3C) recommended its version of the DOM last year.
Netscape now says that in the process of implementing support for the W3C DOM, Level 1, it will not make Communicator 5.0 backward-compatible with some of its own proprietary DOM technology.
Version 5.0's "contract is to fully support DOM1/CSS1/HTML 4.0," wrote Communicator senior product manager Eric Krock in a post to the "netscape.public.mozilla.layout" newsgroup last week. "We unfortunately lack the time and resources to do that *and* support either of the two legacy proprietary DOMs (IE4 and Nav4), so we're going to focus on doing the W3C standards right, providing a robust, unchanging, standard platform going forward."
Krock wrote that abandoning so-called backward compatibility was "a difficult decision...The simple truth is that we are facing the iron triangle of time, resources, and features."
Communicator will continue to support these basic functions written to the proprietary DOM. But more advanced techniques that enable Dynamic HTML (DHTML), a term used by Netscape and Microsoft to refer to a number of new interactive Web technologies, will no longer be supported in Communicator 5.0 if they were written to the Netscape proprietary standard. That means developers will have to rewrite those pages using the W3C DOM recommendation if Communictor 5.0 is to be able to read them.
"Sacrificing backwards compatibility does mean that there will be some pain for developers," said George Olsen, project lead for the Web Standards Project, a developer group that has lobbied Netscape successfully in the past to speed the adoption of standards including the W3C DOM. "On the other hand, the pain may not be that bad because most developers were avoiding extensive use of the DOM because of the existing incompatibilities."
Krock agreed that the difficulties of writing to both Netscape's and Microsoft's incompatible DOMs had prevented most developers from using the technology in the first place.
"The good news is that precisely because it was so painful to write applications that supported both proprietary DOMs, very few people have done it," Krock said. "Navigator 4 and [Microsoft's] Internet Explorer 4 made DHTML possible but difficult because the DOMs were incompatible." The absence of a widely implemented standard DOM "has been retarding the Web from moving to the next level."
Krock promised developers that Netscape would provide help for Web authors who need to continue to support both the proprietary and standardized versions.
"Incompatible DOMs are a problem the vendors created; the vendors have to solve this problem," Krock wrote to the developers. "Netscape urges all other browser vendors to join us in this effort."
Microsoft said Internet Explorer 5.0 included support for the W3C DOM, but the Web Standards Project has criticized IE's W3C DOM implementation.
In related news, Netscape today released version 4.61 of Communicator, with a new security certificate from VeriSign and unspecified bug fixes.