Up until very recently, the void between the Web and the desktop seemed like a schism that could not be crossed. But since AIR‘s 1.0 release in February this year, a whole host of other applications are emerging to compete with AIR in the single site browser space.

Although AIR is very new, the product is remarkably mature with the integration of the excellent opensource WebKit browser engine for rendering HTML and JavaScript, the SQLite database engine for embedded database functionality and of course, Adobe’s Flash player for development of Flash-based Rich Internet Applications. Because of this flexibility, the learning curve faced by developers is almost non-existent, they simply have to get to grips with the AIR API.

What is all the fuss about?

Delving into the AIR API, your application will have the ability to detect whether it is currently the active window or connected to the network. You can access the file system, allowing you to read and write files, access other datasources, tap into the native menu options or interact with almost any aspect of the operating system in a way familiar to common desktop applications. This functionality is available regardless of the architecture on which it is installed. Therefore AIR applications will work similarly when installed on a Windows PC or Mac, and soon on Linux machines as well.

AIR is much, much more than a single-site browser — it’s a cross-platform runtime environment and the distinction is significant.

The ability to run applications built on AIR on almost any machine, on- and offline, sets it apart from any other offering currently out there or in development. For example, Google Gears is restricted to AJAX applications, whilst Mozilla Prism isn’t much more advanced than a cut-down version of Firefox, with no offline capabilities yet.

Who else has entered the race?

As mentioned, a significant entry is Mozilla’s Prism, however, Pyro for Linux and Bubbles and Fluid for Mac are clever little tools for packaging up an existing website and presenting it as a standalone desktop application.

Mozilla Prism

Prism, previously known as WebRunner is a product in development which integrates web applications with the desktop, allowing web applications to be launched from the desktop and configured independently of the default web browser. It is commonly used with Google AJAX Applications, such as Gmail and Google Docs.

Prism is part of an experiment by Mozilla designed to “bridge the divide in the user experience between web applications and desktop applications”. Essentially, Prism will allow you to create a desktop-like application out of individual websites. These site-specific applications are a growing trend and a trend heavily marketed by, not only Adobe, but now Mozilla, as ‘the future’.

While traditionally users have interacted mostly with desktop applications, more and more of them are using Web applications. But the latter often fit awkwardly into the document-centric interface of Web browsers.

In its current form, Prism doesn’t have the ability to function as a desktop application without access to the Internet, but Mozilla says it is “working to increase the capabilities of those apps by adding functionality to the Web itself, such as providing support for offline data storage and access to 3D graphics hardware.”

More details can be found on the Mozilla Prism website.

Pyro Desktop

Pyro Desktop is a new type of desktop environment for Linux built on Mozilla Firefox. Its goal is to enable true integration between the Web and modern desktop computing. Pyro was announced during GUADEC 2007 and is developed by Alex Graveley and Chris Toshok.

More details can be found on the Pyro Desktop website.

3D3R Bubbles

Bubbles is a desktop application that allows you to work with your web resources in the way you want to work with them.

The Bubbles application window, known simply as a Bubble carries the web resource almost like a web browser does. Since the Bubble has advanced browser capabilities there’s an advanced control device for it — the Bubble seed — an XML file called Smart Bubble. It defines the properties — the whats & the hows — of its Bubble window. The Smart Bubble contains the information about what Bubble will load, how it will look on the desktop and what capabilities it will have, etc. So it goes from the Smart Bubble into a grown Bubble that lives on your desktop, accessible from the system tray.

More details can be found on the 3D3R Bubbles website.

Fluid App

Fluid is a way to create Site-Specific Browsers SSBs to run each of your favorite WebApps as a separate desktop application. Fluid gives any WebApp a home on your Mac OS X desktop complete with Dock icon, standard menu bar, logical separation from your other web browsing activity, and many other goodies.

Fluid includes optional Tabbed Browsing, built-in Userscripting (aka Greasemonkey/GreaseKit), RSS/Atom Feed detection, a JavaScript API for setting dock badges, showing Growl notifications and adding Dock Menu Items, optional bookmarks, optional browsing to urls outside the SSB “home” domain, Dock badges and Dock menus for Gmail, Google Reader, Facebook, Flickr, and Yahoo! Mail, auto-software updates via the Sparkle Update framework, and custom SSB icons.

More details can be found on the Fluid App website.

Download the ActionScript reference for RIA development (PDF 1.3MB)

The Adobe technology platform contains two primary runtimes. Flash Player is browser-based, and Adobe AIR is desktop-based. Because Adobe AIR is built on top of Flash Player, the Flash Player APIs are available within Adobe AIR. Consequently, Adobe AIR APIs are not available within Flash Player. The Flex framework is built on top of the Flash Player APIs, so it runs in both Flash Player and Adobe AIR. However, a number of Flex APIs take advantage of AIR APIs, and thus work only within Adobe AIR.

More information about this guide can be found on the Adobe Developer Centre Website.