Mozilla Labs has dumped its Prism project, that was intended to bring web applications to the desktop, in favor of a revamped and repurposed Chromeless that provide yet another way to create a desktop app using web technologies.
There is always the possibility that a new technology will emerge from the depths and surprise everyone with a new twist and turn on technology. One of the dark breeding places of such "lurkers" is Mozilla Labs which has been playing with a range of technologies but mostly XUL (pronounced ZUUL).
Back in 2007 Mozilla created a project, Prism, to bring web applications to the desktop. The basic idea was to convert a web site into a desktop application that could appear to be run without the involvement of the browser. The user gained some fairly small advantages like system tray icons and uniformity of launching. The same idea has been implemented in IE9 in a less well developed form as "pinning" and in Google's Chrome as an application shortcut.
Prism was useful but it really didn't catch on (Zimbra being the exception). It wasn't developed into the Firefox 4 era and basically stagnated. Recently a new project, Chromeless, appeared and was described as a way to create custom browser user interfaces. It was considered an experiment with a browser facility. But of course if you spend a few minutes thinking about it "creating a browser with a custom interface" translates to "creating a web app". Who cares that you could describe the UIs ancestor as a browser if it looks like an organiser or a spreadsheet or a messaging center.
As far as anyone is concerned a Chromeless app is just that an app.
So if Chromeless is a way of creating desktop web using applications who needs Prism?
To be honest there really isn't a great deal of connection between the two projects and killing off Prism to feed Chromeless, which is what Mozilla Labs has done, doesn't make a lot of sense. Prism provided a way that the end user could use to create desktop apps. Chromeless is for programmers to do the same job.
However Chromeless is now Mozilla's way of creating web apps. As the announcement says:
"The final change we’re announcing today takes the form of widening of the goal of the Chromeless project, that is specifically, we now want to Make it possible to build desktop applications with Web technologies."
This too is not new. Microsoft got there first with HTA HTML Applications that could run on the desktop. You build the UI out of DHTML and made it work with either VBScript or JScript. Chromeless uses XUL and runs via XULRunner and it uses a few additional APIs to interact with the operating system.
The biggest barrier to using Chromeless or any XUL based API is finding out how it all works. The documentation and tutorials for XUL and the related technologies are dense and difficult for a beginner to follow. If Mozilla wants this technology to become more wide spread then it should start a project to make XUL easy to use.
So is Chromeless a revolution about to happen?
Build your own browser with Chromeless