Five AJAX Frameworks Reviewed

prostoalex writes "Dr. Dobb's Journal reviews 5 AJAX frameworks: Dojo 0.3.1, Prototype and Scriptaculous 1.4, Direct Web Reporting 1.0, Yahoo! User Interface Library 0.11.1 and Google Web Toolkit 1.0. Each framework was tested in two basic scenarios — writing a 'hub' (titled collapsible link list frequently seen on sidebars of many Web sites) and a 'tab panel' (horizontal tabbed navigation bar). During the process, Dr. Dobb's Journal reviewers noted that 'Dojo provides more features and HTML widgets than YUI and Prototype' but eventually 'settled on the Yahoo! User Interface Library.'"

Comments

Frameworks

[AKAImBatman]

Am I the only one who usually finds frameworks to be pointless for serious web development? It's not that they're necessarily bad, but that they pack in dozens of features that you don't necessarily need (potentially bloating the size of your page download by tens to hundreds of K) or even want. In many cases, the frameworks have a ton of little "gotchas". For example, Prototype has a set of functions that are supposed to make it easy to show and hide elements. The only problem is that if you define the "display" element in the style sheet (say, to make an element invisible by default) you can't change the element's state. This is because the Prototype library works in a stateless fashion, assuming that the default value for "display" is the way to make an item visible. Which may not be not be true.

Other libraries have some cool GUI widgets, but often those are actually too much for a project. In some cases they even require you to build the entire project out of their widgets! That's nice if you're writing the next Outlook on the Web, but not so nice if you're trying to add interactive elements to an existing webpage. Especially if you like the more open HTML design rather than the cluttered pseudo-GUI design.

In general, I've found that these libraries may be kind of nice if you're not too familiar with DOM/CSS and want to perform some neat effects. (Scriptaculous in particular does some nice effects without a whole lot of difficulty. Just watch the download size!) But if you're doing a complex website, you'll probably be better off with a custom library for now. At least until some standard practices emerge among professional sites.

Now if you want to talk about libraries that patch minor browser issues like no DOM 2 Events, lack of Object.toSource, unified XMLHttpRequest instantiation, etc., then I'd have to jump in and add glowing support for such pieces of code. The key is, though, that they're very passive libraries. You include them, and they make sure that your code works the same everywhere. Which is a bit different than being forced to structure your project around a framework. If there's one thing I love about Javascript, it's that everything is virtual. ;)

Re:Frameworks

[profplump]

And I could show you inefficiencies and poorly-formed code and design patterns in projects that do use Struts/Shale/WebWork.

That's not to say that frameworks aren't useful for some purposes, but "enforcing well-formed code and design patterns" is not one of those reasons, nor is failing to use frameworks evidence of bad design.

Re:Frameworks

[AKAImBatman]

Frameworks are what professionals use - the enforce well-formed code and design patterns.

Funny thing, though. We "professionals" (I like the insinuation there, BTW) use the right tool for the right job. Sometimes the right tool is NOT someone else's framework. Sometimes, you're actually creating inefficiencies by adding layers unnecessary to the project at hand. Only an amateur selects a server-side framework before knowing the requirements of the project. The "professionals" will use off the shelf if it makes sense or build their own if better results can be achieved.

In the case of Javascripting, you've got a lot of factors working against you. The first is size. You can't afford waste, because you're trying to ensure that the page renders as fast as possible. Dumping 100K+ from the scriptalicious framework just to fade out a single box isn't very effective to your budget. Especially since the same effect can be achieved in a few hundred bytes by using a custom framework.

The second factor working against you is reusability. Javascript is not very well designed to handle this area. Object Oriented concepts we take for granted in Java (interfaces, abstract classes, private methods, final assignments, etc.) are not enforceable in vanilla Javascript. So you have to either be really clever (sounds like trouble), or work through standardized practices.

The third factor working against you is maturity. These frameworks are of varying levels of maturity because such web technologies are anything but old-hat yet. There are plenty of situations they are untested in, potentially leaving you debugging someone else's code rather than moving your project forward. Thus a framework may actually increase your project time if you're not careful.

And with that, there's one last note I'd like to point out. Frameworks are far too often chosen as a crutch rather than a time-saving component. Make sure that when you chose a framework, it's because you know it will do the job you need it to. Not because you heard it's the latest craze (bad), or because you have no idea how to implement the functionality it provides (even worse).

Re:Frameworks

[PietjeJantje]

Am I the only one who usually finds frameworks to be pointless for serious web development? It's not that they're necessarily bad, but that they pack in dozens of features that you don't necessarily need

This was my problem in the open source project, partly Ajax driven, I'm involved in. Exactly for this reason it sported custom coded Javascript from the start. I don't want to load 50K+ javascripts, and I don't want one big script with crap I don't need. If you have some fairly basic stuff which doesn't change much, it's much more efficient to hand-code your own javascript. Also, when this problem arose, and it is still true, these libaries are relatively brand new, and I found it silly to commit a codebase to any of them. However, if you do all your own coding, there are problems such as cross-browser compatibility, and also there is a certain threshold of complexity when you find you're factoring out the same code and problems, and one should consider a switch. But it is a dangerous point which should be a warning sign by itself, because it could imply your stuff is getting too bloated.

It turned out jquery (jquery.com) was the best choice in our case, it addresses exactly my worries by sporting a size of just 20KB, all extras come in modules, and it's very powerful. I'd rather have a 10K version, but there you have it, you can't have it all. How it (or I) work, is to load the core when the page is loaded, and only insert additional scripts (mostly dynamic, i.e. when you click something) when needed. Similary, Yahoo! has a fine, modulized lib which is extremely well documented.

Last but not least it must be noted that all of these frameworks use MIT/BSD style licenses, and I'd like to thank them all for their great tools and generosity.

Re:Frameworks

[drix]

In fact your very own logic argues for the use of a JS framework. Anything you write that relies on Prototype is going to be far more mature and reusable than something you cobbled together on your own. When I say "mature", I mean it in the holistic sense. It's very, very unlikely that you are you going find some trivial error in the core Prototype library. It's virtually certain that you would do so if you write your own. Maybe you will get them worked out by deployment time, maybe not. Second, Prototype has a rich and consistent API, and anyone who has experience writing applications on top of it could easily pick up your code and reuse it. Finally, you make no mention of cross-browser compatibility, which makes me wonder how much experience developing these sorts of applications you really have. Words cannot describe how much time you save when your starting point is something that works out of the box in IE, Firefox, Safari and Opera. You could sink literally hundreds of hours into testing your application on various platforms. Fortunately, you don't have to, because someone already did. Why reinvent the wheel?

Re:Frameworks

[moochfish]

I disagree. If your goal is to write a website for mom, it is overkill to look at Prototype (maybe). However, anybody who is comparing frameworks is probably way beyond the simple stuff.

As for the bloat issue, this is where libraries like Scriptaculous are doing it right by keeping classes of components in separate libraries. Second, this is why browsers cache JS files. Third, if you want cool effects that are cross-browser compatible, you simply have to accept that such effects come with bloat. If bloat is a show stopper, then you probably shouldn't use fading transitions with scaling div boxes anyway.

And if the argument is that these add way too much *unused* bloat, this comes back to the "mom's website" argument I made above. If people want to use machine guns to hunt cockroaches, that's their call. Unlike with a machine gun, if Prototype is too much, you can always cut out the small pieces you need. That's right -- people seem to conveniently forget that if they only really need one small, tiny part of a much larger library, they're always free to simply cut and paste that component out (MIT license is a great thing, huh).

What? But you need the rest, just in case? Then don't complain about the bloat you are willfully accepting. But in all honesty, Prototype's foot print is tiny -- about the size of an extra image banner -- and it gets cached.

I have been using Prototype extensively lately, and I have found it as a major time saver. By using it, I don't have to remember the various undocumented "gotchas" across browers. I'd much rather deal with the well documented show/hide issue than trying to figure out how to make transparent text in all of the browsers. On that note, did you know Prototype tries to prevent the very "gotchas" you talk of? For example, stopping event propogation is the same method no matter what browser you are using, and the Element.setStyle/getStyle methods correctly convert the 'opacity' property depending on the browser being used. So for whatever "gotchas" you are using to discredit Prototype, I think you are conveniently ignoring the hundreds of others that Prototype strives to fix, silently, without the developer ever knowing.

And lastly, about the notion of writing your own custom library -- that's hardly an option for most people. First of all, most web developers are not JavaScript experts. In fact, I've almost never seen someone use exception handling in JavaScript, short of in libraries like these. More importantly, even if you were some kind of JavaScript guru, are you going to test all of your methods in all of the browsers out there? Can you guarantee your AJAX calls work the same in all browsers? What happens if I trigger a second one during the first one? Is your implementation really more efficient than Prototype's? How long is it going to take to design this custom library? Is it extensible? Does it respect the global namespace? Does it play nice with other JS files I include? Does it work in strict/quirks mode? Like I said, writing such a library isn't an option for most people. Prototype is as close as it gets to a "patch" library, which is why so many other frameworks are built on it. That, and it has been extensively tested, which is a requirement for most companies rolling out technologies like it.