10 Best Practices for Developing JavaScript Widgets

I’d like to offer updated, practical recommendations to developers who are building widgets. Widgets are essentially a mini-application within your web app that provides specific functionality, for example the map switcher widget included as a screenshot in this post. In May 2010, the OpenAjax Alliance published the Metadata 1.0 specification to define a set of standards for widgets. This was a great start, however in the last two years there have been some significant advancements which render some potions of this spec aged and in need of updating. And, since I’ve run across quite a few widgets in the last several years that seem to consistently have certain problems, this post attempts to provide guidelines for anyone looking to make their widgets significantly more re-usable.

State and Display Properties. All widgets need to make their State accessible via public setters and getters which, at a minimum, includes visible/not visible. Getter properties simply offer developers a way to determine whether the widget is visible or not. So, I add that there also needs to be a way to set the State as visible/not visible. Advanced widgets also need control over inline and block positioning.

Persistence. Widgets need the ability to maintain certain aspects of State and persist between app or browser restarts. For example, primary text fields should be persistent after an end user restarts the browser. The corollary is that there also needs to be functionality to clear persisted data.

View Transitions.Widgets must also persist fully and correctly through view transitions. This has to do with mobile web apps designed to mimic native app functionality that occurs when a user switches between different views within the same app.

Auto-resize. Widgets must auto-resize to their container. The sheer popularity of smartphones and tablets is driving this requirement. For example, when a phone is turned on its side, a widget should automatically fill the new dimensions of the container. If your widget doesn’t auto-resize it will significant limit it’s marketability for mobile devices.

Events. Widgets must have a clearly defined life cycle that is accessible via events. At a minimum this includes when the widget is initialized, after specific actions, and upon an errors. Events need to fire when they are expected to and not before or after. This is especially important for mobile apps where event bubbling, or even CPU/Memory overload, may cause delays in the callback. A properly wired event will fire as expected 100% of the time.

Namespace. Widgets must use name space separation so as to not cause variable and function conflicts. For example, don’t name your widget Class “AppWidget”, a best practice alternative is to call it “com.mycompany.AppWidget”. This also includes protecting your global variables to reduce “leakage” outside of your Classes.

Public Properties and Methods. Only properties and methods that are internal should be kept private. All other properties need to be public.

Documentation and Code Comments. This is an age-old problem. Here’s another way to look at it: in many cases, lack of documentation costs other developers significant lost time, effort and money. The one to two minutes a developer saves by not writing a comment could cost another developer hours, days or weeks of frustration.

Cross-platform compatibility. Clearly document which platforms the widget was tested on. If you haven’t been testing your widgets cross-platform then you need to be. If you only designed your widget for a specific browser, that’s okay as long as it’s documented. At a minimum, truly cross-platform widgets will have been tested on the latest production versions of Firefox, Chrome, iPad/iPhone (Safari), Android (native) and IE.

Debugging. If your widget uses an obfuscated JavaScript library, consider providing either a debug version, or a version that includes public (debuggable) methods alongside the private and obfuscated ones.

7 Critical Things to Know When Building Any Mobile App

This blog post builds on concepts proposed in an earlier post about not all mobile apps being created equally. If you are a developer who is in the process of migrating to mobile this post is for you. It’s intended to raise awareness of important items to consider in your requirements. My goal is to help you identify some of the major gotchas early on in the development process and improve your chances for success.

There are many more details to learn on the topics I’ve described below. The good news is that in the last few years the amount of deeply helpful documentation has expanded considerably. Where possible I’ve tried to include links related to each topic.

Touch-based Workflows. Recent research has shown that people use their smartphones more often than web apps, and they spend roughly 80% of their time on social media and games. Because of this and the fact that smartphones today are touch driven and not mouse driven, you have to take that into account in your user interface design. Touch implies many things including gestures and multi-touch. You can toss your old conceptions of user interface design based on desktops and tablets, and check out Android’s recommendations as well as Apple’s. My strong recommendation is to hire a UX designer to help you through building a user interface.

Mutliple form factors come with various screen sizes and densities. Long gone are the days of building for just three main browser types. Now you have to take into consideration iPhones, iPads, tablets, numerous different style androids as well as desktop and laptops. Android defines the following screen sizes and, as you can see, this is quite varied and smaller than a typical laptop or desktop. Those typically run 1024 x 768 or greater.

  • xlarge screens are at least 960dp x 720dp
  • large screens are at least 640dp x 480dp
  • normal screens are at least 470dp x 320dp
  • small screens are at least 426dp x 320dp

This is important to know because an app that looks good on an iPad may not look good, or display correctly, on the four inch display of a Motorola Atrix at 960 x 540. A button that looks correctly sized on one smartphone may look too big on another. A whopping 84% of all Android screens are what Android defines as normal size (>=  470dp x 320dp) and between either medium dpi (~160dpi) or high dpi (~240dpi). But, you still have to take into consideration other densities. I also recommend taking a look at new HTML5 browser-based technologies to help with addressing this problem, such as CSS media queries.

Inconsistent Internet. It’s a best practice to check if internet connections exist and gracefully handle HTTP requests when the internet is down, as I blogged about here.  Depending on your application and needs, you should also monitor whether or not a wireless connection can be made and then allow the application to switch to wireless where possible. Wireless also has the advantage of using less battery power.

Slower Connections. And, on a related note, you can’t always depend on 4G connections having consistent maximum download speeds. Over the course of a user session, the connection speed will vary widely and you should plan for that. I’ve been trying to find some stats on mobile internet quality world-wide, if they are out there they are hard to find. But, we’ve all experience spotty mobile internet coverage. Take this into account if you are transferring large amounts of data between your servers and your app. You should also consider detecting when the user is in an area of greater bandwidth and use that to download more data less often. Use loosely coupled and event driven architectures. Test app load times on various devices and around town and away from your office.

Less CPU Horsepower. While the latest generation of four core phones are certainly the most powerful phones yet. In general, applications and web pages will run slower on phones than they do on your development machine running a desktop browser. Take older generation phones into account because they are usually significantly slower than the newer phones. There are a few workarounds in HTML5 to help with this, in that done correctly they can offload rendering to the hardware. In native applications be aware of memory leaks because, remember, more memory usage means less battery life and applications that can run slower over time.

Support across multiple operating system versions. Remember on Android that the vast majority of users are still running v2.2 – v2.3.7 even though v4.x is currently shipping. You’ll have to do some research on your target market and find out what versions and type of phones they are using. You can’t support everything, but you can make educated guesses. Apple, on the other hand, has a significantly more limited selection of phones and tablets that you have to support, and they do a great job helping you support those.

There are some solutions that help with building cross-platform mobile apps, to go into more detail will take another blog post. Here’s a few: Adobe Flex, PhoneGap and Titanium. Keep in mind that the future of Flex, as a development platform, is being called into question after Adobe open sourced everything but the browser and desktop runtimes to the Apache Foundation. PhoneGap and Titanium offer what is now being called “hybrid” solutions where you can build an application in JavaScript, for example, and then compile that code for native deployments on Android and iOS.

Battery Life. Ah, battery life is last but certainly not least. Be aware of how battery intensive your application is and try to minimize battery consumption as much as possible. The Android online docs have a number of highly information articles on this subject. Smaller app footprint in memory means less battery consumption. Heavy CPU usage means more battery usage. Minimize GPS usage through smart algorithms to help preserve battery life.  Switch to 802.11 wireless connections where possible, since this requires less battery power than 3G and significantly less power than 4G.

So, there you go. I hope these suggestions help. If you have more suggestions based on your own experience please post a comment!

References:

Android Gestures

Android Optimize Battery Life

Android Screen Sizes and Densities

CSS media queries

Android UI Design

Android Model for Best GPS Performance

iOS User Experience

HTML5 Hardware Acceleration

Event-based Architectures for Adobe Flex

Mozilla + Firefox über-release cycle = #FAIL! The long tail of costs and risks associated with fast release cycles.

Dear Mozilla Foundation, according to your web site you promote openness, innovation and participation. So, I feel strongly enough to write you about a problem. You are pushing for too many major releases in too short of time. If it wasn’t for firebug and httpfox developer tools, I’d dump Firefox as my browser of choice right now. In my humble opinion they are still the best web developer tools around…for now. But back to my point, and note that this isn’t a rash or knee jerk response: Firefox 7 appears to be the least stable browser I’ve used in a long time, Period. I’ve had a dozen lock-ups, problems on startup and various slow page load problems.  

I haven’t added any new plug-ins that might de-stabilize it. In fact, I’ve been using the same set of plug-ins since Firefox 3.x. And, I haven’t had any similar widespread problems with the latest versions of Internet Explorer or Chrome. You might ask “What if it’s just your machine?” To that I say I’ve experienced this on four different machines, and many of my colleagues share the same opinion. So Mozilla, I’m hanging on by my fingertips and you are stomping on them.

The Heart of the Problem

Maybe I’m the exception, but I believe that getting cool new browser features every few months at the expense of stability is the wrong choice. I’ve said this before in another post and I’ll say it again. I’ve read countless articles saying this is what Mozilla has to do to stay competitive. I say you couldn’t be more wrong and that there needs to be a more balanced approach to major releases. Now, I’m not implying that you, Mozilla, are intentionally leaving stability or scalability behind. I’m saying that the massive rush to stay abreast of new features being released by your competitors has to come at a cost, and I believe the cost for Firefox, at this point in time, is stability.

So, in response to an outcry over this and other related problems, and in order to counteract some of the side-effects of your über -release cycle, you will begin offering Extended Support Release, or ESR, sometime in the next year. I interpret this as an attempt to mitigate the über -release cycle’s short-term and long-term risks and costs on Enterprise customers by offering an extending support cycle for a limited number of releases and time. But…readers of this post must read the fine print under the Caveats and Risks sections; for example, ESR’s won’t apply to Firefox Mobile at a time when mobile usage is exploding. And, the ESR makes note of the security risks of staying on an “older” release. Fair enough. However one possible conclusion is, on the surface, ESRs seem like a mere concession to a looming problem, and perhaps it is a stop gap measure at best. Perhaps I’m wrong?

Driving Factors

I want to ask Mozilla the following questions:

  • What’s coming up in your next release?
  • Are the changes really so fundamental that the next release has to be a major numbered version?
  • What metrics are you using to make your decisions?
  • How fast are your users upgrading to new versions world-wide?
  • Is the new version adoption rate trending upward or downward?
  • Who are your largest supporters? Large organizations or the millions of individual users?
  • Have you taken a public survey from your largest supporters of what they would like to see?

Now, of course, this post is just my opinion, and I’m willing to admit that I may be seeing this problem in the wrong light or a different context. But, I and a lot of others want to know what you are thinking.

Hypothetical Scenario

Here’s a hypothetical scenario on how an organization might interpret the ESR, and I speak for myself on this one and am simply presenting one outcome of possibly many. Mozilla will continue to blast along having thirteen more major releases between now and March of 2013*. In response, CIO’s of major organizations will start to choose a pattern of leap frogging across swaths of major releases. In response, their development and IT teams will focus on building web apps, along with a full test suite and certification for Firefox 7. Then their next fully tested and certified release will be targeted at Firefox 9 sometime next year. These organizations may choose to not even support Firefox 8 because it’s between their development and certification cycles. There’s also a long-tail of cost associated with maintaining numerous previous releases across a multitude of browser versions from all the major vendors. In effect, these CIOs will weigh the security risks, costs and other issues over the costs of deploying an army of IT folks and developers to keep up with the über -release cycle.

Concluding Remarks

Mozilla I hope you are listening. You should take the following steps to reduce the possibility of failing as a leading browser vendor:

Focus on stability – IMHO, Firefox appears to be paying the price in the rush to add new and supposedly better features. I’m not even sure what those are because your release process isn’t transparent. As your consumer, first and foremost I would like my browser to be rock solid, followed by speed, followed by snazzy features. Rock solid to me also means that it’s as secure as possible. “Dot” releases are okay and in general they ease the support-related fears from both developers and IT teams.

Slow down the release cycles – Mozilla, you already acknowledged there’s a problem when you proposed the ESRs, but you need to go further than acknowledgement and a pat on the back which is what I consider ESRs to be. Seriously.

Now, I know I didn’t address these above, but I’m throwing these into the mix because I think they are strongly related:

Provide guidance on browser certification and best practices – if documentation for this exists today I can’t find it. Building apps on browsers, today in the year 2012, is still like the Wild West in that everyone does what they think is right, but there’s really no word from the Vendor(s) themselves. Most people point to the W3C. But, everyone agrees that what’s agreed upon in the standard is not what’s officially interpreted and implemented by browser vendors in each and every release.

It’s been speculated by others that having browser vendors offer guidelines would crush innovation, and I strongly disagree. It’s your platform we are building on and you know how to do that in the best possible way. Believe it or not, you are also a key caretaker of the internet in that the web, in its current state, wouldn’t exist without the browser. And, I think it’s your responsibility to step up to the plate and help take leadership role, not just a feature-ship role and simply hope that everything turns out okay.

Provide official tools for browser certification – please don’t leave this entirely up to third parties with different goals and objectives. Based on your vast experience in this process, it would benefit everyone if you were to publicly share your tools, patterns, knowledge and guidance. Or, maybe you already do share this with key partners. Yes, you are open source, but not open process. Browsing through your partner sites doesn’t give any indication of publicly available tools.

I believe that the combination of these four goals would help propell Firefox on more successful trajectory than the one us users see today. Without the inclusion of my last two suggestions, as an application developer I’m hoping my code will work as best as possible, without truly knowing what that means. Is what we are doing simply good enough, or could we all do better? What are your recommendations on patterns for best performance or even unit testing for various languages? I can’t help but believe that you hold the key to that level of knowledge, as well as methodologies and tools that can help Firefox help us deliver on the next generation of web applications.

References

*Mozilla release schedule

Mozilla rapid-release schedule

Mozilla Defends Rapid Release of FireFox Versions (CIO Magazine, August 2011)

Improving Browser performance and stability – will web workers help?

The single-threaded nature of JavaScript is an old tradition that needs to go away. It was great in the wild-west, internet days of the 20th century. But, today we have more complex needs that are being driven by the advancements that are happening around good old JavaScript as we know it, such as…on-going advancements in HTML 5.  

The reason I bring this up is because I’ve been watching the discussion on Web Workers as it has evolved.  It’s a brave attempt to bring a standard for implementing some sanity on this ancient notion of single threading. Now, I do want to say that this post isn’t about debating the merits of web workers, per se. It’s about giving developers better tools on which to build web applications for end users. I’ll be the first to agree that many developers (but not all!), for a variety of reasons, build apps like factories, but without many quality checks.

One argument the pro-single threaded parties claim is that doing away with single-threading will make things even more complicated for the companies that develop browsers and the developers that build apps on them. And, in effect, you’d be giving them (web app developers) free license to create even more terribly built web pages that crash browsers.  For brevity sake, I’m only picking this one out of many possible arguments, as the one that comes up most often in discussions.

I also don’t ever recall seeing a browser vendor themselves saying something like this publicly, but it’s possible.  This is a very weak argument that won’t stand the test of time. Sure, as we build more complex apps then there will be more of both good and bad apps. That’s just the way things work. There’s no way we would ever have a single authority that reviews all web apps before they are published. Perhaps, similar to what Apple does with iPhone apps. Not only would it be impractical, but it certainly seems like it goes against the spirit of the internet and WWW.

I fall into the camp of evolving the tools to better to fit the ever-changing and growing needs of the end users. End users don’t understand the limitations of the browser technology.  They don’t need to and shouldn’t be expected to. All they know is that they want to see ever more visually stunning applications that run well and don’t crash all the time.

Developer tools and technology are much, much more advanced now than when the venerable Mosaic Web Browser hit the scene back in 1993. As an example, all eyes are on HTML 5 (more on that at a later date), and certainly we have the well-known browser plug-ins: Flash and Silverlight, and each has their own development kits. These technologies enable the building of some of the most eye-catching websites, and they really opened people’s eyes on what the web experience should be more like.

Now, I am eyes-wide-open about this. There are some well-documented, but not well understood existing limitations related to the web surfing/development experience as I blogged about here. But, merely saying things should not change because it will become too complicated isn’t a good enough reason to, well…not change.  There are lots of smart people out there that love solving these types of problems.

So, I have a few suggestions of my own for the browser vendors and others to debate and work on. I think web workers are huge step in the right direction. But I also think there’s some other more strategic things that browser vendors could be doing that I think would also help. To me these are just as important as evolving the web standards, perhaps even more so. This is about browser vendors officially providing guidelines for us on how to do our job better:

  • Best Practices Document. All the major vendors should publish web development best practices for HTML and JavaScript development. And, I’m not talking about the W3C standard. That is what’s expect, but not actually what’s implemented. For example, I did a quick search of “web development best practices” using Google and Bing and the very first result I found was a short, not-really-so-helpful article on the Apple web site that was written in 2008!
  • Online HTML/JavaScript Validation engine(s). Each browser vendor should publish their own online HTML/JavaScript validation engine. Or better yet would be if someone builds one site that checks all major browsers in one shot and provides actionable feedback. I’m aware of other types of validators such as this one by W3C for HTML and the like. But, in general right now it’s just a hodgepodge of 3-rd party tools and guesswork as to whether a web app is working right. And, if you are like me and running the web debugger all the time, you’d know how many broken web pages there really are.

References: