Christian Heilmann

Making your HTML5 efforts worthwhile – #sotb3 talk

Saturday, April 20th, 2013 at 11:06 am

Today I gave a talk at the State of the browser 3 event in London, England. The Slides are here, a screencast (with bad audio) is on YouTube and here are the notes.

When the web was defined as an idea it was based on the principle of independence of hardware, global location, prosperity or ability. This changed drastically when the mobile web came around and we got sucked into a world of software dependent on certain hardware and global location. HTML5 and the mobile web based on open technologies became something that needed conversion to native code to access the new hardware people use. This is against the main principle of the web and means we duplicate efforts all over the place. In this talk Chris Heilmann shows how Mozilla is battling this trend and how brushing up your HTML5 solutions allows you to reach millions of new users forgotten by native technology but nevertheless eager to be online.

When I was a kid, I had an uncle in America and he sent us comic books. One of the things advertised in these comic books were sea monkeys – awesome pets that are a whole society and play with another and anyone can look after. Turns out these things are just Brine Shrimp and don’t look at all like that. Actually they are really ugly and boring.

This is what I feel a bit like when we look at what happened to HTML5 on mobile devices. When the iPhone came out Steve Jobs announced that there is no need for an SDK and that Safari with web technologies is more than enough to deliver great experiences. When I tried though what worked I quickly found myself hindered in a lot of respects and the attitude of Apple towards web technologies on the phone vs. native apps changed drastically and very quickly.

And somehow this lead to a terrible experience of the web on mobile devices. This is especially annoying when the sites have been “optimised for mobile viewing” and still fail to deliver anything useful. Another big thing that is happening right now is web sites redirecting you to download a native app instead. This is not what I want when I am on the go on a limited connection and simply look something up. Brad Frost collects a lot of terrible user experiences on mobile at

What happened? When did we give up on the idea of nice and responsive web products that use what is available to them? It can not be about the tools we have. Browsers have amazing developer tools built into them these days – all of them, really. Using these tools we have very fine-grained control over what happens in a browser.

For example in this shot you can see the difference using requestAnimationFrame instead of setTimeout makes.

Requestanimationframe vs setTimeout

Let’s not forget how far browsers have come in the recent years.
Browsers these days are nothing more but awesome. Whatever you can complain about you can file as a bug and if it is a real issue it can be fixed within weeks. Every few weeks there are browser updates and security fixed happen over night. All of them render HTML the same way.

And yet the web is full of sites that are plain broken on different devices. Simple things like forgetting to define a viewport size can make an interface unusable or really annoying to get around. Why?

Terrible mobile login interface

I think as a community we get far too excited about products. The whole mobile space thrives on hardware sales. So instead of building stable and good solutions we continuously want the newest and coolest and support it exclusively. I remember when Retina displays came out and many voices in the web design community called out that we need to fundamentally change what we are doing now. This is fleeting, and in many cases we aren’t even allowed as web developers to access the new technology that makes a product what it is. You can look very silly, very quickly when chasing the shiny.

One big part of this was people getting too excited about the iPhone and Android as the only platforms to support prematurely calling WebKit the only browser engine worthy of our efforts (effectively repeating the same mistakes we did in the end 90ies which gave us all the fun “IE only” web products). With the announcement of the Blink rendering engine powering Opera and Chrome from here on forward the “webkit only” argument went down the drain. Good riddance.

Firefox OS

How about we give web technologies a new platform on mobile devices? And how about not trying to compete with iOS and Android on high end devices while doing so? This is what Firefox OS is about – it brings the web to people who have mobiles as their main interaction with the web – based on web technologies and without the lock-out.

Here are the main differences that FirefoxOS bring in comparison to Android or iOS:

  • Targeted at new, emerging markets
  • Very affordable hardware
  • No credit card needed – client billing
  • Web technologies through and through
  • 18 mobile partners, 4 hardware partners

Firefox OS was created to bring users of feature phones into the web-enabled mobile world. It is meant to cater to the markets not covered by iOS and Android. Yes, you can buy cheap Androids world-wide but the version of Android they support doesn’t have an out-of-the-box browser that allows you to do interesting things on the web. Much like Firefox and Opera for Android allow more users world-wide to have a great web experience without having the latest hardware, Firefox OS goes further. Its main goal is to bring millions of new users to the web on their mobile devices without getting a second-grade experience.

The search interface of Firefox OS

One huge differentiator of Firefox OS is that instead of solely relying on a market place to list apps, apps can be found by entering what you are looking for. This means that if you enter for example a band name like “u2”, you get music apps offered to you. For a movie title it is apps that have to do with films. These are both apps listed in the market place and web-optimised sites. Say you looked for a band, you could click on the songkick icon and get the mobile interface of songkick. You can try the app before you download it and see if you like it. If you want to install it you just tap it for longer and Firefox OS will install the app – including offline functionality, full-screen interface and the extra hardware access Firefox OS offers. This means your mobile interfaces become the ad for your application and users don’t need to download and install a huge app just to try it out. Everybody wins. We made App discovery as easy as surfing the web.

What makes your HTML5 site and app for Firefox OS is the manifest file:

  "name": "My App",
  "description": "My elevator pitch goes here",
  "launch_path": "/",
  "icons": { "128": "/img/icon-128.png" },
  "developer": {
    "name": "Your name or organization",
    "url": ""

In it you define the name, describe the app, give us info about yourself and which icons to display. You also define the localisations that are available and what access you need to the hardware. Depending on how many things you want to access, you can host the app yourself or you have to get it hosted through our infrastructure. This is a crucial part of keeping the platform secure. We can not just allow any app to make phone calls for example without the user initiating them.

These are the three levels of apps available in Firefox OS. For third party app developers, the first two are the most interesting.

  • Hosted apps – stored on your server, easy to upgrade, limited access.
  • Privileged apps – reviewed by the App store, uses a Content Security Policy, hosted on trusted server
  • Certified apps – part of the OS, only by Mozilla and partners

Apps that run on your own server have all the access HTML5 gives them (local storage via IndexedDB, offline storage via AppCache) and the new WebAPIs defined by Mozilla and proposed as a standard. A few of these APIs are also available across other browsers, for example the Mouselock API or the Battery API.

  • Vibration API
  • Screen Orientation
  • Geolocation API
  • Mouse Lock API
  • Open WebApps
  • Network Information API
  • Battery Status API
  • Alarm API
  • Push Notifications API
  • WebFM API / FMRadio
  • WebPayment
  • IndexedDB
  • Ambient light sensor
  • Proximity sensor
  • Notification

One very important API in this stack is the Open Web Apps API. With these few lines of code you can turn any HTML5 web app into a Firefox OS app by offering a link or button to install it. No need to go through the marketplace at all – you can be in full control of your app.

var installapp = navigator.mozApps.install(manifestURL);
installapp.onsuccess = function(data) {
  // App is installed
installapp.onerror = function() {
 // App wasn't installed, info is in 

All the APIs are kept simple, they have a few properties you can reda out and fire events when there are changes in their values. If you used jQuery, you should be very familiar with this approach. This code, showing the Battery API should not be black magic.

var b = navigator.battery;
if (b) {
  var level = Math.round(b.level * 100) + "%",
      charging = (b.charging) ? "" : "not ",
      chargeTime = parseInt(b.chargingTime / 60, 10),
      dischargeTime = parseInt(b.dischargingTime/60,10);
  b.addEventListener("levelchange", show);
  b.addEventListener("chargingchange", show);
  b.addEventListener("chargingtimechange", show);
  b.addEventListener("dischargingtimechange", show);

If you host your app in the Mozilla Marketplace your app can do more than just the APIs listed earlier. You can for example access the address book, store data on the device’s SD card, connect via TCP Sockets or call third party APIs with XHR.

  • Device Storage API
  • Browser API
  • TCP Socket API
  • Contacts API
  • systemXHR

For a hosted, privileged app it is simple to create a new contact. That enables you for example to sync address books across services. As with all the other APIs, you get an event handler that gets fired on success or failure.

var contact = new mozContact();
contact.init({name: "Christian"});
var request =;
request.onsuccess = function() {
// contact generated
request.onerror = function() {
// contact generation failed

Certified apps – apps built by Mozilla and partners have full access to the hardware and can do everything on it, including calls and text messaging and reading and writing permissions as well as accessing the camera.

  • WebTelephony
  • WebSMS
  • Idle API
  • Settings API
  • Power Management API
  • Mobile Connection API
  • WiFi Information API
  • WebBluetooth
  • Permissions API
  • Network Stats API
  • Camera API
  • Time/Clock API
  • Attention screen
  • Voicemail

One question we get a lot is why hosted apps on your own server couldn’t get full access to the camera and the phone – something that always is an annoyance on iOS which is why we need to use something like phonegap to create native code from our HTML5 solutions. The reason is security. We can not just allow random code not in our control to access these devices without the user knowingly allowing it every time you want to access this functionality.

If however, you are fine for the user to initiate the access, then there is a way using web activities. This for example is the result of asking for a picture:

Pick activity

The user gets an interface that allows access to the gallery, the wallpaper or to the camera. Once a photo is picked from any of those, the data goes back to your app. In other words, web activities allow you to interact with the native apps built into the OS for the purpose of storing, creating and manipulating a certain type of data. Instead of just sending the user to the other app you have a full feedback loop once the activity was successfully done, or cancelled. This is similar to intents on Android or pseudo URL protocols on iOS, with the difference that the user gets back to your app automatically.

There are many predefined Web Actitivies allowing you to talk to native apps. All of these are also proposals for standardisation.

  • configure
  • costcontrol
  • dial
  • open
  • pick
  • record
  • save-bookmark
  • share
  • view
  • new, f.e type: “websms/sms” or “webcontacts/contact”

For example this is all the code needed to send a phone number to the hardware. For the user it would switch to the dialer app and they have to initiate the call. Once the call is hung up (or could not be connected) the user gets back to your app with information on the call (duration, and the like).

var call = new MozActivity({
  name: "dial",
  data: {
    number: "+1804100100"

To get a picture from the phone you initiate the pick activity and specify an image MIME type. This offers the user all the apps that store and manipulate images – including the camera – to choose.

var getphoto = new MozActivity({
  name: "pick",
  data: {
    type: ["image/png", "image/jpg", "image/jpeg"]

Again, a simple event handler gets you the image as a data blob and you can play with it in your app.

getphoto.onsuccess = function () {
  var img = document.createElement("img");
  if (this.result.blob.type.indexOf("image") != -1) {
    img.src = window.URL.createObjectURL(this.result.blob);
getphoto.onerror = function () { // error

The great news is that if you have Firefox on Android, this functionality is also available outside of Firefox OS for you – any Android device will do.

I hope you are as excited as we are and you are ready to have a go at playing with these APIs and Activities. But where to start?

The Firefox OS Developer Hub is the one-stop-shop for everything Firefox OS. There you can find information on what makes a good HTML5 app, play and download example apps to change into yours and find information how to submit your app to the marketplace or how to publish it yourself. You also get information about monetisation and how to set up a development environment (basically installing the simulator).


The simplest way to test out Firefox OS is to install the Simulator, which is just an add-on for Firefox. Once installed you can test your apps on your server or on your local hard-drive in a Firefox OS instance running in an own thread and an own window. You can get all kind of feedback about your app working in Firefox OS with the developer console and the error logs.

alt=”Boilerplate App” height=”400” class=”middle shadow”>

Firefox OS Boilerplate is a demo app that has stub code for all the different Web Activities. You can try them out that way and just delete the ones you don’t need. It is a great demo app to get started with and base your efforts on.


Sooner or later you’d want to test your app on a real device though. The easiest way to do that is to get a developer phone from These have the same specifications as the Firefox OS phones sold in the markets our partners are targeting. These are now ready for pre-order and the shop should be live soon.

Even if you don’t care for Firefox OS or don’t want to build something for it, rest assured that it will have an impact on the current mobile web. A whole new group of users will emerge and the mobile version of your site will become a calling card for them to get interested in your offers. And if anything, HTML5 is supported by every player in the market, so now is a good time to brush up what is out there. This is what Firefox OS brings you – and soon:

  • A whole new audience
  • HTML5 without the lock-out
  • Your web site is your ad!
  • Minimal extra work, it works across platforms

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