InformationWeek

Internet View

By Jason Levitt

t's hard to imagine ei ther Microsoft or Netscape Communications trying to reconcile implementation differences between Netscape Communicator and Microsoft Internet Explorer 4.0, but a recent gesture by Microsoft would appear to be doing exactly that. However, the move isn't very meaningful because it actually promotes Microsoft's Channel Definition Format (CDF).

Microsoft has proposed changing the CDF specification to add, among other things, an anchor element that could potentially let Netscape's Netcaster push client navigate CDF files. The CDF specification, which is written using XML (eXtensible Markup Language), an extendible version of SGML (Standard General Markup Language) that may replace HTML in the future, uses tags that can't be interpreted by current browsers or by Netcaster. By adding the common HTML anchor tag, <A HREF="...url...">, to the CDF specification, Netcaster could read the CDF file, see the links specified by the anchor tags (Netcaster would ignore the other CDF tags), and "crawl" to them, thereb y accessing the same content that IE 4.0's push client would access.

The obvious problem is that Netcaster won't try to read a CDF file. That's because a CDF file uses the file extension .cdf, not the .html or .htm suffixes used by HTML files. One way around this is to go to the Web server and change the MIME type returned by files ending with .cdf so Netcaster will know the file contains HTML data. But that might cause a problem with IE 4.0, which wants to treat CDF files as CDF files, not HTML files.

I'm optimistic about the chance of Netscape and Microsoft finding common ground for their push technologies, and I think CDF is a better way to go. Interestingly, I've noticed that Microsoft is downplaying the Subscriptions feature in IE 4.0, which is similar to Netcaster in that they both rely on Web crawling. Microsoft wants users to view Subscriptions as a convenience feature of IE, not a real push technology.

A more sensible solution would be a Java applet or Netscape plug-in that could let Comm unicator access CDF files. DataChannel Inc. in Bellevue, Wash., has a demo of one such applet that is part of its greater Java-based push solution. You can try out a demo at www.datachannel.com.

I'm sure we'll see a few more solutions soon, and that will help developers and Webmasters focus on doing interesting things with push technology instead of hacking sites to make them compatible with IE 4.0 and Communicator.

You can read his Internet Zone column on InformationWeek Online at techweb.cmp.com/iw/author/internet.htm .

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