I’ve been hearing a lot of Flash vs. Ajax arguments lately, and unfortunately, they almost always start off in the wrong way.
It’s very common to hear people argue about Flash websites or RIAs vs. Ajax websites or RIAs, but this is always the wrong way to approach building any website. Would you have an argument with an architect about whether to build a house out of wood vs concrete? Of course not, they would use each material to build the parts of the house that the respective material is best for. Sometimes you might want to build a shack or barn out of all wood, sometimes you might want to build an all brick house, but many times you’ll want to use the best material for each section of the house. Build the foundation out of concrete, the walls and roof out of wood.
Websites and web applications should be treated the same way. Break things down to a component level and go from there. Use the right tool for each component. If you can do it well with HTML/Javascript, go for it. If it would work out better with Flash, then why waste time recreating something with Javascript that you could build 3 times faster with Flash? There are plenty of great examples of this today around the internet:
One of my favorite examples is Google Finance. They use HTML and Javascript for the stuff that is best suited for that, and then when they need to show a nice graph, they drop in a great interactive Flash graph and talk to it using Javascript as needed. The Flash controls the Javascript, and the Javascript can control the Flash as needed.
Another example is Flickr. They started out using Flash to display all of the images, including the image notes and the other toolbar options along with each image. While this might have been a good choice as the site started out, it was soon replaced by a more efficient HTML version of the toolbar and notes system that works just as well as the Flash version. They did end up keeping one small bit of Flash so users can rotate images and see a preview before they save it.
So the next time you start planning a website and you start thinking: “Hmm, Flash or Ajax?” Instead of looking at it from a site-wide perspective, try thinking about your site as a series of components, and then choose Flash or HTML/Javascript for each individual component instead.