AJAX alliance to start interoperability work

Funny how, after an initial development rush, a community around a new technology will hit some interoperability issues, and then start to address it via some kind of specification initiative. AJAX, the browser-side interaction technique that brought you google maps, is in that phase right now.

Making Asynchronous JavaScript and XML (AJAX) work smoothly matters, not only because it can help make webpages more engaging and responsive, but also because it is one of the most rapid ways to build front ends to web services.

It may seem a bit peculiar at first that there should be any AJAX interoperability issues at all, since it is built on a whole stack of existing, mature, open standards: the W3C’s XML and DOM for data and data manipulation, and XHTML for webpages, ECMAScript (JavaScript) for scripting and much more besides. Though there a few compliance issues with those standards in modern browsers, that’s not the actually the biggest interoperability problem.

That lies more in the fact that most AJAX libraries have been written with the assumption that they’ll be the only ones on the page. That is, in a typical AJAX application, an ECMAScript library is loaded along with the webpage, and starts to control the fetching and sending of data, and the recording of user clicks, drags, drops and more, depending on how exactly the whole application is set up.

This is all nice and straightforward unless there’s another library loaded that also assumes that it’s the only game in town, and starts manipulating the state of objects before the other library can do its job, or starts manipulating completely different objects that happen to have the same name.

Making sure that JavaScript libraries play nice is the stated aim of the OpenAjax alliance. Formed earlier this year, the alliance now has a pretty impressive roster of all the major open source projects in the area as well as major IT vendors such as Sun, IBM, Adobe and Google (OpenAjax Alliance). Pretty much everyone but Microsoft…

The main, concrete way in which the alliance wants to make sure that AJAX JavaScript libraries play nice with each other is by building the OpenAjax hub. This is a set of standard JavaScript functions that address issues such as load order and component naming, but also means of addressing each other’s functionality in a standard way.

For that to happen, the alliance first intends to build an open source reference implementation of the hub (OpenAjax Alliance). This piece of software is meant to control the load and execution order of libraries, and serve as a runtime registry of the libraries’ methods so that each can call on the other. This software is promised to appear in early 2007 (Infoworld), but the SourceForge filestore and subversion tree are still eerily empty (SourceForge).

It’d be a shame if the hub would remain vapourware, because it is easy to see the benefits of a way to get a number of mature and focussed JavaScript libraries to work in a single Ajax application. Done properly, it would make it much easier to string together such components rather then write all that functionality from scratch. This, in turn, could make it much easier to realise the mash-ups and composite applications made possible by the increasing availability of webservices.

Still, at least the white paper (OpenAjax Alliance) is well worth a look for a thorough non-techy introduction to AJAX.