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To Flash or not to Flash: Methods for presenting dynamic content

By Leonard Martin and Jethro Jessop, 17th April 2009

Adobe (formerly Macromedia) Flash began life in 1996 as a tool for creating simple animated and interactive content for web pages. Since its release, many additional features have been added; most notably a powerful scripting language - ActionScript - and facilities for playing multimedia content such as video and audio. These advances have opened the door to a world of applications ranging from the simple animations for which it was orignally conceived, to fully featured Rich Internet Applications (RIAs).

It is the use of Flash in RIAs which has made it ubiquitous across many areas of the web and in turn attracts criticism from some corners. One of the accusations most frequently levelled at Flash is that it "breaks" accessibility. Flash's ability to present a rich and engaging user experience is a boon to the typical web user, but a lack of support for accessibility features such as keyboard navigation and screen-reader software can severely inhibit the browsing experience of a disabled web user. In addition, many usability and interface conventions to which a user may be accustomed are often not adhered to.

In light of these potential shortcomings, it is important to consider whether the use of Flash is strictly necessary for presenting dynamic content and RIAs to the user. Since the release of "next-generation" browsers (such as Firefox 3 and Google Chrome) and their improved CSS support and JavaScript engines, working in conjunction with modern JavaScript frameworks, it is possible to achieve a wide variety of visual effects without deviating from a traditional HTML document approach.

Historically, JavaScript has been used as a means of providing simple dynamic or interactive functionality within an HTML page. Its use in this way became widespread in the late 90s, but a lack of attention to usability, combined with poor levels of cross-browser support caused its use to fall out of favour with the majority of web developers for all but basic tasks. In recent years, with the emergence of the "web 2.0" ideal, we have seen a resurgence in the use of JavaScript in a number of new and innovative ways, many of which can now rival Flash in the delivery of RIAs.

By leveraging modern JavaScript techniques and frameworks, it is now possible to take advantage of the familiar user interface (UI) which an HTML based application can provide. Examples of this can be seen in such frameworks as jQueryUI (based on the jQuery framework) or script.aculo.us (based on the prototype framework) which provide a range of UI widgets and visual effects in an easy to implement form.

By developing in this fashion, it is possible to achieve a progressive enhancement by which a single application can be created using pure HTML/CSS in conjunction with server side logic to reliably present your content to all users, and then apply layers of additional functionality to the user using JavaScript techniques where they are available and applicable.

None of this is to say that Flash has no place on the modern web, it remains an incredibly powerful tool for creating the type of rich visual content which would never be possible using a "traditional" approach. However, careful consideration should be given as to whether its use is appropriate given the many alternatives which are now available.