This is a topic I’ve been delving into for some time (Flex or AJAX :: A Quick Litmus Test), as I’ve had the pleasure to implement production solutions with both Flex and Ajax; while I’m a diehard proponent of Flex, I gotta give Ajax some respect for bringing RIAs to the masses — that simple little acronym unknowingly brought me more RIA (again, both Flex / Flash and Ajax) work than my team can even handle!
…and so it seems it’s time for another round of the Flex vs. Ajax debate, with Forrester taking a stab this time: Ajax Or Flex?: How To Select RIA Technologies. Or, you can read Ryan Stewart’s and / or Yakov Fain’s quick summary of it…and if you’re too lazy to click to those, you can take away this extremely short version of it all: Flex is one, robust library / framework backed by Adobe, whereas Ajax usually includes choosing a framework (usually a tedious, in-depth process within itself…trust me…dojo still does it for me though, as it proves to offer the most extensive library at least backed by some of the major players) and a development tool-set backed by many or no one of consequence — I nabbed from Ryan’s summary of the report because it also hit home with me:
Choosing a commercial Ajax solution means adopting a proprietary framework and development tools. In this light, commercial Ajax vendors look more like Adobe than like open source Ajax tool kits.
I’m also still a fan of pushing the Flash Platform over Ajax for the following reasons:
Unified Cross Browser / Platform User Experience:
- One virtual machine means one rendering engine means one code base and one set of coding standards.
- Ajax / DHTML applications are subject to each browser’s implementation of the DOM and often require developers to provide workarounds for each variation thereof; this inherently creates additional, unnecessary code and ultimately adds to the development timeline. Large Ajax applications with rich user experience = large development effort.
- While many Ajax / DHTML toolkits exist to facilitate this shortcoming by abstracting browser inconsistencies, they’re often extremely large in file size, immature, lack standards and documentation and ultimately fall short of a complete solution.
What’s Your Application Platform?
- The Flash Platform provides a true application platform as a virtual machine that’s browser / platform independent, including a JIT compiler and strong typing.
- The very intention for the Flash Player was to provide a container to perform operations like rendering complex animations and filter thousands of data sets at the same time, thus providing a desktop-like experience with comparable performance on the internet.
- AJAX applications leverage the browser as the application platform, which is something it was never intended to be used for. The browser is nothing more than a text-based rendering engine, and was never conceived as a container for complex, client-side applications.
- The performance implications of running a complex Ajax application are subject to the browser’s ability to interpret JavaScript and determine the type at runtime is it a string, a number, an object? whereas ActionScript 3 (AS3) eliminates type look-up because its strongly typed and compiled into bytecode rendered by the Flash Player VM this facilitates better responsiveness in your application.
Development Models
- The Flex workflow and programming model follow a more traditional approach familiar to application developers. Flex applications are implemented using a combination of declarative tags (MXML) for the user interface / presentation and a scripting language (ActionScript) for complex business / application logic.
- MXML is an XML based, declarative language that’s similar to HTML and is used for layout.
- ActionScript is a strongly typed, classed based OO language analogous to Java, but with the flexibility of a scripting language.
- While the MXML and AS aren’t native to most traditional app developers, the development paradigm is a similar model to that of JSP and Java development, making it an easy transition for seasoned developers.
- Flex Builder offers a professional IDE based on Eclipse, with the usual myriad of tools an application developer expects.
- Debugging is built on top of the Eclipse Debugging Framework and provides common tools like setting breakpoints and watching variables
- While Ajax is the mesh of several, common client-side technologies, overcoming the browser compatibility issues often requires expert knowledge of each browsers interpretation of the DOM, and usually leads to hack-like workarounds. Even if you’re using an Ajax / DHTML toolkit, you’re still subject to the pains of cross browser issues.
- Ajax often entangles both HTML and JavaScript to create rich user interfaces where the end result is a tightly coupled client application that’s often difficult to maintain and extend.
So then there’s the final question of openness…Ajax (and it’s encompassing technologies are all open)..what about Flex? This was a question that stumped me for some time…I used to just say, open, what are going to do with it even if the Flash Player is open? Are you going to create your own version of the FP so it branches like Java did years back, cuz yeah, that worked…and then I realized I needed to be a bit more practical with my response and read this: How truly open is Flash? Do we need “Open Flash”?
At the end of the day, I’m still going to arm myself with Flex as the weapon of choice in the RIA war. Perhaps the release of Apollo and other desktop-like browser apps will be the tell-tale.
