AJAX, Flash, Silverlight, or JavaFX: Must We Choose ...

AJAX has forever altered user expectations regarding the experience delivered by the Web. In today’s world, users sit at the edge of their seat waiting to see what scrumptious eye candy AJAX will serve them next. Some of the more notable visual effects and desktop-like interactions include Prototype-esque fades, Dojo style fisheyes, the near ubiquitous drag-and-drop, and, of course, who can live without the entertainment provided by the assortment of animated loading icons that now distract us while AJAX does its asynchronous “thing.” Yes, it would appear that AJAX can do it all and that no desktop visual effect or gesture is safe from being outsourced to the Web.

Is the AJAX Revolution Over?
Does this mean AJAX has met its match? Not at all. It’s true that Adobe Flash and similar technologies compete with AJAX, but there are certain limitations to these HD RIA frameworks that prevent them – for the time being – from being an out right replacement for AJAX without some considerable due diligence. Here are a few of the more notable things to consider when deciding between HD RIA solutions and AJAX:

• Plug-in required: HD RIA solutions require a browser plug-in. As of March 2007, 83.4% of PCs in the U.S., Canada, UK, Germany, France, and Japan have the Flash 9 player installed. Thus, it is arguable that Flash is virtually ubiquitous. However, even with a near universal install base, the need to upgrade a plug-in can be disruptive. More than half of users prompted to upgrade a plug-in upon visiting a site often abandon the redirect to download software and navigate to another site – possibly a competitor’s site – in an effort to avoid the hassle of downloading and installing software. Note that neither JavaFX nor Silverlight currently enjoy a fraction of the market share owned by the Adobe Flash Player. Also note that the 83.4% market share enjoyed by Flash 9 pales in comparison to the native AJAX support found in modern browsers such as IE 7.0, FireFox 2.0, and Safari 3.0.

• Lack of open standards: AJAX, unlike HD RIA solutions, is built on open standards such as (X)HTML, CSS, and JavaScript. HD RIA is traditionally proprietary with few open source options, much less standards. JavaFX, initially introduced as an open source effort, appears to be the leader at this time in terms of changing the status quo for HD RIA solutions, but it is by far the least evolved.

• Skills scarcity: Flex, Silverlight, and JavaFX each introduce its own respective language(s). AJAX on the other hand, relies on JavaScript, which is relatively well known, and is readily combined with other popular technologies such as Ruby-on-Rails, PHP, Java, and .NET.

• Does not play well with HTML: For new applications developed entirely with Flex this is not so much an issue, but for existing applications it can be a considerable problem. AJAX and, moreover, JavaScript, were created to complement HTML. The Flash runtime on the other hand lacks the flexibility to manipulate the structure of existing HTML pages with the ease that the JavaScript DOM object provides.

• Large download footprint: Flash-based RIA solutions tend to have a larger download footprint than solutions that rely on native AJAX support (e.g., Dojo, ICEFaces, Backbase, or Oracle ADF Faces Rich Client). The consequence of a larger download is a prolonged wait during application startup.

• Searchable, but not always found: In recent years, search engines have introduced the ability to index swf files into their respective Web crawlers. Yahoo and Google are the most well-advertised supporters of the file format, though the methodology used is not widely published or well understood. To optimize search results, Web designers often build both a Flash and a traditional HTML site or opt for embedded Flash movies within a traditional HTML site as an adornment to text-based content. Note that at the time of writing this article I could not procure information on how or when search engines will address this issue with emerging HD RIA technologies such as JavaFX and Silverlight.

• All clients are not created equal: With newer PCs, this concern is becoming less of a factor, but since HD RIA environments make heavy use of client resources to execute business logic as well as render visual effects, application performance is governed by the configuration of the client machine. Therefore, the user experience can vary from machine to machine. AJAX-based solutions that come with an inherited server-side component (e.g., Oracle ADF Faces Rich Client) can utilize server resources to off load both processing and rendering to ensure more uniform delivery to clients.

The reader should note that none of the considerations listed should prevent you from choosing Flash or similar products over AJAX. AJAX is certainly not without its own faults – many of which have, in recent years, had more visibility than those found in HD RIA solutions. Some of the more prominent issues that come to mind include slow JavaScript execution, memory leaks, numerous browser bugs, two connection limits, and CSS rendering issues. Simply put, to create an application on the order of Google Maps or GMail with AJAX, you must not be opposed to any manner of hackery. In addition, this article has already identified cases where HD RIA solutions outperform AJAX-based solutions, specifically in the realm of rendering vector graphics. But, at the other end of this equation it is apparent that AJAX is better suited for incremental updates to existing applications than say Flash or other HD RIA solutions, and AJAX is also better equipped to handle text-based content, which is currently the prominent medium for content on the Web – though, the more media-centric, real-time driven Web 3.0 might tip the scale to a richer format in the near future. Thus, currently no RIA solution on the market is absent of limitations.

Fortunately, the limiting factors of both AJAX and HD RIAs are – in general terms – mutually exclusive. Therefore, AJAX and technologies such Flash actually complement each other well and, as sites such as YouTube and SlideShare have proven, can be combined to create robust applications that provide both rich media and dynamic text. But, this introduces yet another dilemma and that is – not all developers are created equal, which conjures up the question of whether this concoction of RIA solutions is achievable by mere mortals?

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2 Comments |Add your comment.

Rommert said:

The strength of AJAX is the open-standards part. Sure, you can build web apps with JavaFX, Flash or Silverlight. But the problem is that they completely miss SEO, Accessibility and common semantics. In my opinion, JavaScript should be further developed (and standardized) to improve its implementations.

Posted at November 15, 2007 10:41:43 am

Asd said:

1. JavaFX runs on Java and doesnt require anything else installed (at the moment anyway), so its current install base is pretty good.2. JavaFX can call all your Java code3. JavaFX or Silverlight are likely to be far far more efficient than current Javascript implementations so even if you are doing more work they will probably perform better.

Posted at November 13, 2007 04:18:38 pm

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