Web designers often seek tools that can bring static elements to life, and CSS keyframes are a great ally for this task. Keyframes enable us to animate elements over a certain duration, providing our designs with a dynamic feel. Below, …

Julie Grundy kicks off this, our fifteenth year, by diving headlong into the snowy issue of customising form inputs. Nothing makes a more special gift at Christmas that something you’ve designed and customised yourself. But can it be done while staying accessible to every user?

In my work as an accessibility consultant, there are some frequent problems I find on people’s websites. One that’s come up a lot recently is that people are making custom select inputs for their forms. I can tell that people are trying to make them accessible, because they’ve added ARIA attributes or visually-hidden instructions for screen reader users. Sometimes they use a plugin which claims to be accessible. And this is great, I love that folks want to do the right thing! But so far I’ve never come across a custom select input which actually meets all of the WCAG AA criteria.

Often I recommend to people that they use the native HTML select element instead. Yes, they’re super ugly, but as Scott Jehl shows us in his article Styling a Select Like It’s 2019 they are a lot easier to style than they used to be. They come with a lot of accessibility for free – they’re recognised and announced clearly by all screen reader software, they work reliably and predictably with keyboards and touch, and they look good in high contrast themes.

But sometimes, I can’t recommend the select input as a replacement. We want a way for someone to choose an item from a list of options, but it’s more complicated than just that. We want autocomplete options. We want to put images in there, not just text. The optgroup element is ugly, hard to style, and not announced by screen readers. The focus styles are low contrast. I had high hopes for the datalist element, but although it works well with screen readers, it’s no good for people with low vision who zoom or use high contrast themes.

Select inputs are limited in a lot of ways. They’re frustrating to work with when you have something which looks almost like what you want, but is too restricted to be useful. We know we can do better, so we make our own.

Let’s work out how to do that while keeping all the accessibility features of the original.

Semantic HTML

We’ll start with a solid, semantic HTML base. A select input is essentially a text input which restricts the possible answers, so let’s make a standard input.

<label for="custom-select">User Type</label>
<input type="text" id="custom-select">

Then we need to show everyone who can see that there are options available, so let’s add an image with an arrow, like the native element.

<label for="custom-select">User Type</label>
<input type="text" id="custom-select">
<img src="arrow-down.svg" alt="">

For this input, we’re going to use ARIA attributes to represent the information in the icon, so we’ll give it an empty alt attribute so screen readers don’t announce its filename.

Finally, we want a list of options. An unordered list element is a sensible choice here. It also lets screen reader software understand that these bits of text are related to each other as part of a group.

<ul class="custom-select-options">
  <li>User</li>
  <li>Author</li>
  <li>Editor</li>
  <li>Manager</li>
  <li>Administrator</li>
</ul>

You can dynamically add or remove options from this list whenever you need to. And, unlike our <option> element inside a <select>, we can add whatever we like inside the list item. So if you need images to distinguish between lots of very similar-named objects, or to add supplementary details, you can go right ahead. I’m going to add some extra text to mine, to help explain the differences between the choices.

This is a good base to begin with. But it looks nothing like a select input! We want to make sure our sighted users get something they’re familiar with and know how to use already.

Styling with CSS

I’ll add some basic styles similar to what’s in Scott Jehl’s article above.

We also need to make sure that people who customise their colours in high contrast modes can still tell what they’re looking at. After checking it in the default Windows high contrast theme, I’ve decided to add a left-hand border to the focus and hover styles, to make sure it’s clear which item is about to be chosen.

This would be a good time to add any dark-mode styles if that’s your jam. People who get migraines from bright screens will thank you!

JavaScript for behaviour

Of course, our custom select doesn’t actually do anything yet. We have a few tasks for it: to toggle the options list open and closed when we click the input, to filter the options when people type in the input, and for selecting an option to add it to the input and close the list. I’m going to tackle toggling first because it’s the easiest.

Toggling

Sometimes folks use opacity or height to hide content on screen, but that’s like using Harry Potter’s invisibility cloak. No-one can see what’s under there, but Harry doesn’t cease to exist and you can still poke him with a wand. In our case, screen reader and keyboard users can still reach an invisible list.

Instead of making the content see-through or smaller, I’m going to use display: none to hide the list. display: none removes the content from the accessibility tree, so it can’t be accessed by any user, not just people who can see. I always have a pair of utility classes for hiding things, as follows:

.hidden-all {
  display: none;
}

.hidden-visually {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    -webkit-clip-path: inset(50%);
    clip-path: inset(50%);
    border: 0;
} 

So now I can just toggle the CSS class .hidden-all on my list whenever I like.

Browsing the options

Opening up our list works well for our mouse and touch-screen users. Our styles give a nice big tap target for touch, and mouse users can click wherever they like.

We need to make sure our keyboard users are taken care of though. Some of our sighted users will be relying on the keyboard if they have mobility or dexterity issues. Usually our screen reader users are in Browse mode, which lets them click the arrow keys to navigate through content. However, custom selects are usually inside form elements. which pushes screen reader software to Forms Mode. In Forms mode, the screen reader software can only reach focusable items when the user clicks the Tab key, unless we provide an alternative. Our list items are not focusable by default, so let’s work on that alternative.

To do this, I’m adding a tabindex of -1 to each list item. This way I can send focus to them with JavaScript, but they won’t be part of the normal keyboard focus path of the page.

csOptions.forEach(function(option) {
    option.setAttribute('tabindex, '-1')
}) 

Now I can move the focus using the Up and Down arrow keys, as well as with a mouse or tapping the screen. The activeElement property of the document is a way of finding where the keyboard focus is at the moment. I can use that to loop through the elements in the list and move the focus point forward or back, depending on which key is pressed.

function doKeyAction(whichKey) {
  const focusPoint = document.activeElement
  switch(whichKey) {
    case: 'ArrowDown':
      toggleList('Open')
      moveFocus(focusPoint, 'forward')
      break
    case: 'ArrowUp':
      toggleList('Open')
      moveFocus(focusPoint, 'back')
      break
  }
}

Selecting

The Enter key is traditional for activating an element, and we want to match the original select input.

We add another case to the keypress detector…

case 'Enter':
  makeChoice(focusPoint)
  toggleList('Shut')
  setState('closed')
  break 

… then make a function which grabs the currently focused item and puts it in our text input. Then we can close the list and move focus up to the input as well.

function makeChoice(whichOption) {
    const optionText = whichOption.documentQuerySelector('strong')
    csInput.value = optionText
}

Filtering

Standard select inputs have keyboard shortcuts – typing a letter will send focus to the first item in the option which begins with that letter. If you type the letter again, focus will move to the next option beginning with that letter.

This is useful, but there’s no clue to tell users how many options might be in this category, so they have to experiment to find out. We can make an improvement for our users by filtering to just the set of options which matches that letter or sequence of letters. Then sighted users can see exactly how many options they’ve got, and continue filtering by typing more if they like. (Our screen reader users can’t see the remaining options while they’re typing, but don’t worry – we’ll have a solution for them in the next section).

I’m going to use the .filter method to make a new array which only has the items which match the text value of the input. There are different ways you could do this part – my goal was to avoid having to use regex, but you should choose whatever method works best for your content.

function doFilter() {
  const terms = csInput.value
  const aFilteredOptions = aOptions.filter(option => {
    if (option.innerText.toUpperCase().startsWith(terms.toUpperCase())) {
    return true
    }
  })
  // hide all options
  csOptions.forEach(option => option.style.display = "none")
  // re-show the options which match our terms
  aFilteredOptions.forEach(function(option) {
    option.style.display = ""
  })
} 

Nice! This is now looking and behaving really well. We’ve got one more problem though – for a screen reader user, this is a jumble of information. What’s being reported to the browser’s accessibility API is that there’s an input followed by some clickable text. Are they related? Who knows! What happens if we start typing, or click one of the clicky text things? It’s a mystery when you can’t see what’s happening. But we can fix that.

ARIA

ARIA attributes don’t provide much in the way of additional features. Adding an aria-expanded='true' attribute doesn’t actually make anything expand. What ARIA does is provide information about what’s happening to the accessibility API, which can then pass it on to any assistive technology which asks for it.

The WCAG requirements tell us that when we’re making custom elements, we need to make sure that as a whole, the widget tells us its name, its role, and its current value. Both Chrome and Firefox reveal the accessibility tree in their dev tools, so you can check how any of your widgets will be reported.

We already have a name for our input – it comes from the label we associated to the text input right at the start. We don’t need to name every other part of the field, as that makes it seem like more than one input is present. We also don’t need to add a value, because when we select an item from the list, it’s added to the text input and therefore is exposed to the API.

But our screen readers are going to announce this custom select widget as a text entry field, with some images and a list nearby.

The ARIA Authoring Practices site has a pattern for comboboxes with listboxes attached. It tells you all the ARIA you need to make screen reader software give a useful description of our custom widget.

I’m going to add all this ARIA via JavaScript, instead of putting it in the HTML. If my JavaScript doesn’t work for any reason, the input can still be a plain text field, and we don’t want screen readers to announce it as anything fancier than that.

csSelector.setAttribute('role', 'combobox') 
csSelector.setAttribute('aria-haspopup', 'listbox')
csSelector.setAttribute('aria-owns', '#list') 
csInput.setAttribute('aria-autocomplete', 'both')
csInput.setAttribute('aria-controls', 'list')

The next thing to do is let blind users know if the list is opened or closed. For that task I’m going to add an aria-expanded attribute to the group, and update it from false to true whenever the list changes state in our toggling function.

The final touch is to add a secret status message to the widget. We can use it to update the number of options available after we’ve filtered them by typing into the input. When there are a lot of options to choose from, this helps people who can’t see the list reducing know if they’re on the right track or not.

To do that we first have to give the status message a home in our HTML.

<div id='custom-select-status' class='hidden-visually' aria-live='polite'></div>

I’m using our visually-hidden style so that only screen readers will find it. I’m using aria-live so that it will be announced as often as it updates, not just when a screen reader user navigates past it. Live regions need to be present at page load, but we won’t have anything to say about the custom select then so we can leave it empty for now.

Next we add one line to our filtering function, to find the length of our current list.

updateStatus(aFilteredOptions.length)

Then we send that to a function which will update our live region.

function updateStatus(howMany) {
    console.log('updating status')
    csStatus.textContent = howMany + " options available."
}

Conclusion

Let’s review what we’ve done to make an awesome custom select input:

• Used semantic HTML so that it’s easily interpreted by assistive technology while expanding the types of content we can include in it
• Added CSS styles which are robust enough to survive different visual environments while also fitting into our branding needs
• Used JavaScript to provide the basic functionality that the native element has
• Added more JavaScript to get useful functionality that the native element lacks
• Carefully added ARIA attributes to make sure that the purpose and results of using the element are available to assistive technology and are updated as the user interacts with it.

You can check out my custom select pattern on GitHub – I’ll be making additions as I test it on more assistive technology, and I welcome suggestions for improvements.

The ARIA pattern linked above has a variety of examples and customisations. I hope stepping through this example shows you why each of the requirements exists, and how you can make them fit your own needs.

I think the volume of custom select inputs out there shows the ways in which the native select input is insufficient for modern websites. You’ll be pleased to know that Greg Whitworth and Simon Pieters are working on improving several input types! You can let them know what features you’d like selects to have. But until that work pays off, let’s make our custom selects as accessible and robust as they can possibly be.

About the author

Julie Grundy is an accessibility expert who works for Intopia, a digital accessibility consultancy. She has over 15 years experience as a front-end web developer in the health and education sectors. She believes in the democratic web and aims to unlock digital worlds for as many people as possible. In her spare time, she knits very slowly and chases very quickly after her two whippets.

More articles by Julie

Laura Kalbag discusses the gift of personal data we give to Big Tech when we share information on its platforms, and how reviving ye olde personal website can be one way to stay in control of the content we share and the data we leak. Christmas is a time for giving, but know what you’re giving to whom.

Is it just me or does nobody have their own website anymore? OK, some people do. But a lot of these sites are outdated, or just a list of links to profiles on big tech platforms. Despite being people who build websites, who love to share on the web, we don’t share much on our own sites.

Of course there are good reasons people don’t have their own websites. For one, having your own site is something of a privilege. Understanding hosting packages, hooking up a domain name, and writing a basic HTML page are not considered the most difficult challenges for a web designer or developer – but they often require intimidating choices, and the ability to wield that knowledge with confidence tends to come with repeated experience.

Buying a domain and renting web hosting doesn’t cost much, but it does cost money, and not everyone can afford that as an ongoing commitment. Building and maintaining a site also takes time. Usually time nobody else is going to pay you for doing the work. Time you could be be spending making the money you need to pay the bills, or time you could be spending with your family and friends.

A personal website also creates personal pressure. Pressure to have things worth sharing. Pressure to be cool and interesting enough for a personal site. Pressure to have a flashy design, or a witty design, or the cleverest and cleanest code. Pressure to keep the site updated, not look like you lost interest, or stopped existing after your site was last updated in 2016.

We are sharing

Most of us share loads of expressive and personal stuff with each other: status updates, photos, videos, code snippets, articles and tutorials. Some people only do these things in social contexts, like those who live on Instagram. Some only in workplace contexts, like the performative professionalism of LinkedIn. And plenty of people mix the two together, like those of us who mix dog photos and tech news on Twitter.

Many of us find sharing what we learn, and learning from each other, to be one of the few joys of working in the web community. One of the reasons web design and development as practices are accessible to people regardless of their background is because of those who believe sharing back is a fundamental element of community. A lot of us taught ourselves how to design and code because of those who shared before us. Our work often depends on free and open frameworks and packages. Our practices evolve at a rapid rate because we share what we’ve learned, our successes and our failures, to benefit others who are working towards the same goals.

But we’re sharing on other people’s platforms

Big Tech has given us a load of social platforms, and the content we’ve shared on those platforms has made them valuable. These platforms are designed to make it easy and convenient to share our thoughts and feelings. And they don’t cost us any money. The social nature of the platforms also make us feel validated. One button press for a like, a love, a star, a share, and we feel appreciated and connected. And it’s all for free. Except it isn’t.

It’s not news anymore that the vast majority of the web is funded by extracting and monetising people’s personal information. Shoshana Zuboff coined the term “surveillance capitalism” to describe this model. Aral Balkan calls it “people farming.” Essentially it means when we are not paying for mainstream tech with money, we are paying for it with our privacy. And sometimes we can pay for tech with money and still have our privacy eroded. (I call this the “have-your-cake-and-eat-it-too model” or the “Spotify model”.)

Many—usually cis, white, heterosexual—people in the tech industry believe that this “privacy tradeoff” is worthwhile. While they have a financial incentive in the continuation of this model, and are not necessarily the worst harmed when their privacy is weakened, their privilege has made them short-sighted. There are many people who are harmed by a model that reinforces stereotypes, discriminates against race, gender and disability, and shares vulnerable people’s information with exploitative corporations and authoritarian governments.

We’re not just making decisions about our own privacy, either. By using a script that sends site visitor information back to somebody else’s server, we’re making our visitors vulnerable. By using an email provider that extracts personal information from our emails, we’re making our contacts vulnerable. By uploading photos of our friends and families to platforms that create facial recognition databases, we’re making our loved ones vulnerable.

Making technology that respects the rights of the people using it isn’t a fun responsibility to take on. It’s also a challenging exercise to weigh our convenience and privilege against exposing other people to harm when life feels difficult already. But we can’t sit back and expect other people/overseers/charities/ombudsmen/deities to fix our communities or industries for us. We’ve got to do some of the work, pay some of the costs, and take responsibility for ourselves. Especially if we are people who can afford it or have the time. We can’t keep prioritising our conveniences over the safety of other people.

One small way to get our independence and agency back from exploitative platforms is to build personal websites to share on instead. Of course, it’s a tiny tiny step. But it’s a step to taking back control, and building a web that neither relies upon, nor feeds, the harms of Big Tech.

Personal websites give us independence and agency

Personal doesn’t have to mean individualistic. Your website might be your own blog, portfolio or hobby project, but it could also be for your community, local team or cause. It could be all about a person, or anonymous. You could use it to showcase other people’s work that you appreciate, such as links to articles you’ve found valuable.

A website doesn’t have to be a fancy work of art that’ll be written up in a hundred publications, a website is just an HTML page. You can even add some CSS if you want to show off.

A home (or an office)

When people ask where to find you on the web, what do you tell them? Your personal website can be your home on the web. Or, if you don’t like to share your personal life in public, it can be more like your office. As with your home or your office, you can make it work for your own needs. Do you need a place that’s great for socialising, or somewhere to present your work? Without the constraints of somebody else’s platform, you get to choose what works for you.

Your priorities

For a long time, I’ve been giving talks about being conscious of the impacts of our work. But when I talk about the principles of small technology or the ethical design manifesto, people often tell me how impossible it is take a stand against harmful practices at their job.

Personal sites give you the freedom to practice the design and development you care about, without the constraints of your boss’s bad business model or your manager’s questionable priorities. We can create accessible and inclusive sites that don’t exploit our visitors. We can experiment and play to work out what really matters to us. If we don’t like our personal site, we can start again from scratch, iterate, change, keep working to make it better.

Your choice of design

Your own personal website means you choose the design. Rather than sharing on a blogging platform like Medium, we can make our design reflect our content and our principles. We don’t need to have ads, paywalls or article limits imposed on us.

No tracking

It does rather defeat the point of having a personal website, if you then hook it up to all the tracking mechanisms of Big Tech. Google Analytics? No thanks. Twitter follow button? I’d rather not. Facebook Like button? You must be joking. One of the benefits of having your own personal site is that you can make your personal site a tracking-free haven for your site’s visitors. All the personal websites I’ve shared here are tracking-free. Trust me, it’s not easy to find websites that value their visitors like this!

Staying connected

A personal website doesn’t mean an antisocial website. Charlie Owen’s site comprises a feed of her notes, checkins, likes, replies, reposts and quotes, along with her longer-form posts and talks.

If you want to go hardcore, you can even run your own social platform instance. I have my own Mastodon instance, where I can post and socialise with other people in the “fediverse,” all from the comfort and control of my own domain.

Freedom from the popularity contest (and much of the harassment)

There’s value to being sociable, but one of the perks of having your own personal site is freedom from follower counts, likes, claps, and other popularity contests that reduce your self-expressions into impressions. It’s nice to know when people like your work, or find it valuable, but the competition created from chasing impressive numbers results in unequal power structures, clickbait, and marginalised people having their work appropriated without credit. A personal site means your work can still be shared but is also more likely to stay in that location, at the same URL, for much longer. You also get the final say over who can comment on your work in your own space. Wave goodbye to the trolls, they can go mutter to themselves under their own bridges.

Your choice of code

As I mentioned earlier, your website doesn’t have to be anything more than an HTML page. (Just think how fast that would load!) With your own personal site, you get to choose what code you want to write (or not write) and which frameworks you want to use (or not use).

As an individual or a small group, you don’t need to worry about scale, or accommodating as many users as possible. You can choose what works for you, even what you find fun. So I thought I’d share with you the whats and whys of my own personal site setup.

Your choice of setup

I use iwantmyname to buy domain names and Greenhost for web hosting. (Greenhost kindly provides Small Technology Foundation with free hosting, as part of their Eclipsis hosting for “Internet freedom, liberation technology developers, administrators and digital rights activists.” You don’t get many benefits in this line of work, so I treasure Greenhost’s/Open Technology Fund’s kindness.)

My blog has ten years’ worth of posts, so I rely on a content management system (CMS) to keep me organised, and help me write new posts with as little fuss as possible. Two years ago, I moved from WordPress to Hugo, a static site generator. Hugo is fine. I wrote my own theme for Hugo because I can, and also because I value accessible HTML and CSS. The setup works well for a personal site.

Now my website is just a self-hosted static site, it’s noticeably faster. Importantly, I feel I have more ownership and control over my own site. The only third-party service my site needs is my web host. As it’s “serverless”, my site also doesn’t have the security risks associated with a server-side CMS/database.

Nowadays, static sites and JAMstack (JavaScript, APIs, Markup -stack) are ultra trendy. While static sites have the aforementioned benefits, I worry about the APIs bit in the JAMstack. With static site generators, we (can, if we want) take out a number of the privacy, security and performance concerns of serverside development, only to plug them all back in with APIs. Every time we use a third-party API for critical functionality, we become dependent on it. We add weakness in the deployment process because we rely on their uptime and performance, but we also become reliant on the organisations behind the API. Are they a big tech platform? What are we paying for their service? What do they get out of it? Does it compromise the privacy and security of our site’s visitors? Are we lending our loyalty to an organisation that causes harm, or provides infrastructure to entities that cause harm?

For all we speak of interoperability and standards, we know we’re unlikely to move away from a shady service, because it’s too deeply embedded in our organisational processes and/or developer conveniences. What if we don’t create that dependent relationship in the first place?

It’s why I use Site.js. Site.js is a small tech, free and open, alternative to web frameworks and tools of Big Tech. I use Site.js to run my own secure (Site.js provides automatic trusted TLS for localhost) development and production servers, and rapidly sync my site between them. It has no dependence on third-parties, no tracking, and comes as a single lightweight binary. It only took one line in the terminal to install it locally, and the same line to install it on my production server. I didn’t need to buy, bolt on or configure an SSL certificate. Site.js took care of it all.

In development, I use Site.js with Hugo to run my site on localhost. To test across devices, I run it on my hostname with ngrok (a tunnelling app) to expose my development machine.

Site.js also provides me with ephemeral statistics, not analytics. I know what’s popular, what’s 404ing, and the referrer, but my site’s visitors are not tracked. The stats themselves are accessible from a cryptographically secure URL (no login required) so I could share this URL with whoever I wanted.

For those who want the dynamic functionality often afforded by third-party APIs, Site.js enables you to layer your own dynamic functionality on top of static functionality. We did this for Small Technology Foundation’s fund page. We wanted our patrons to be able to fund us without us relying on a big tech crowdfunding platform (and all the tracking that comes along with it). Aral integrated Stripe’s custom checkout functionality on top of our static site so we could have security for our patrons without relinquishing all our control over to a third party. You can even build a little chat app with Site.js.

Every decision has an impact

As designers and developers, it’s easy to accept the status quo. The big tech platforms already exist and are easy to use. There are so many decisions to be made as part of our work, we tend to just go with what’s popular and convenient. But those little decisions can have a big impact, especially on the people using what we build.

But all is not yet lost. We can still build alternatives and work towards technology that values human welfare over corporate profit. We’ve got to take control back bit by bit, and building our own personal websites is a start.

So go on, get going! Have you already got your own website already? Fabulous! Is there anything you can do to make it easier for those who don’t have their own sites yet? Could you help a person move their site away from a big platform? Could you write a tutorial or script that provides guidance and reassurance? Could you gift a person a domain name or hosting for a year?

Your own personal site might be a personal thing, but a community and culture of personal sites could make a significant difference.

About the author

Laura Kalbag is a British designer living in Ireland, and author of Accessibility For Everyone from A Book Apart. She’s one third of Small Technology Foundation, a tiny two-person-and-one-husky not-for-profit organisation. At Small Technology Foundation, Laura works on a web privacy tool called Better Blocker, and initiatives to advocate for and build small technology to protect personhood and democracy in the digital network age.

More articles by Laura

Chris Mills brushes up his shorthand and shows how the MediaStream Recording API in modern browsers can be used to capture audio directly from the user’s device. Inching ever closer to the capabilities of native software, it truly is an exciting time to be a web developer.

The MediaStream Recording API makes it easy to record audio and/or video streams. When used with MediaDevices.getUserMedia(), it provides an easy way to record media from the user’s input devices and instantly use the result in web apps. This article shows how to use these technologies to create a fun dictaphone app.

A sample application: Web Dictaphone

To demonstrate basic usage of the MediaRecorder API, we have built a web-based dictaphone. It allows you to record snippets of audio and then play them back. It even gives you a visualisation of your device’s sound input, using the Web Audio API. We’ll just concentrate on the recording and playback functionality in this article, for brevity’s sake.

You can see this demo running live, or grab the source code on GitHub. This has pretty good support on modern desktop browsers, but pretty patchy support on mobile browsers currently.

Basic app setup

To grab the media stream we want to capture, we use getUserMedia(). We then use the MediaRecorder API to record the stream, and output each recorded snippet into the source of a generated <audio> element so it can be played back.

We’ll first declare some variables for the record and stop buttons, and the <article> that will contain the generated audio players:

const record = document.querySelector('.record');
const stop = document.querySelector('.stop');
const soundClips = document.querySelector('.sound-clips');

Next, we set up the basic getUserMedia structure:

if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
   console.log('getUserMedia supported.');
   navigator.mediaDevices.getUserMedia (
      // constraints - only audio needed for this app
      {
         audio: true
      })

      // Success callback
      .then(function(stream) {

      })

      // Error callback
      .catch(function(err) {
         console.log('The following `getUserMedia` error occured: ' + err);
      }
   );
} else {
   console.log('getUserMedia not supported on your browser!');
}

The whole thing is wrapped in a test that checks whether getUserMedia is supported before running anything else. Next, we call getUserMedia() and inside it define:

• The constraints: Only audio is to be captured for our dictaphone.
• The success callback: This code is run once the getUserMedia call has been completed successfully.
• The error/failure callback: The code is run if the getUserMedia call fails for whatever reason.

Note: All of the code below is found inside the getUserMedia success callback in the finished version.

Capturing the media stream

Once getUserMedia has created a media stream successfully, you create a new Media Recorder instance with the MediaRecorder() constructor and pass it the stream directly. This is your entry point into using the MediaRecorder API — the stream is now ready to be captured into a <Blob>, in the default encoding format of your browser.

const mediaRecorder = new MediaRecorder(stream);

There are a series of methods available in the MediaRecorder interface that allow you to control recording of the media stream; in Web Dictaphone we just make use of two, and listen to some events. First of all, MediaRecorder.start() is used to start recording the stream once the record button is pressed:

record.onclick = function() {
  mediaRecorder.start();
  console.log(mediaRecorder.state);
  console.log("recorder started");
  record.style.background = "red";
  record.style.color = "black";
}

When the MediaRecorder is recording, the MediaRecorder.state property will return a value of “recording”.

As recording progresses, we need to collect the audio data. We register an event handler to do this using mediaRecorder.ondataavailable:

let chunks = [];

mediaRecorder.ondataavailable = function(e) {
  chunks.push(e.data);
}

Last, we use the MediaRecorder.stop() method to stop the recording when the stop button is pressed, and finalize the Blob ready for use somewhere else in our application.

stop.onclick = function() {
  mediaRecorder.stop();
  console.log(mediaRecorder.state);
  console.log("recorder stopped");
  record.style.background = "";
  record.style.color = "";
}

Note that the recording may also stop naturally if the media stream ends (e.g. if you were grabbing a song track and the track ended, or the user stopped sharing their microphone).

Grabbing and using the blob

When recording has stopped, the state property returns a value of “inactive”, and a stop event is fired. We register an event handler for this using mediaRecorder.onstop, and construct our blob there from all the chunks we have received:

mediaRecorder.onstop = function(e) {
  console.log("recorder stopped");

  const clipName = prompt('Enter a name for your sound clip');

  const clipContainer = document.createElement('article');
  const clipLabel = document.createElement('p');
  const audio = document.createElement('audio');
  const deleteButton = document.createElement('button');

  clipContainer.classList.add('clip');
  audio.setAttribute('controls', '');
  deleteButton.innerHTML = "Delete";
  clipLabel.innerHTML = clipName;

  clipContainer.appendChild(audio);
  clipContainer.appendChild(clipLabel);
  clipContainer.appendChild(deleteButton);
  soundClips.appendChild(clipContainer);

  const blob = new Blob(chunks, { 'type' : 'audio/ogg; codecs=opus' });
  chunks = [];
  const audioURL = window.URL.createObjectURL(blob);
  audio.src = audioURL;

  deleteButton.onclick = function(e) {
    let evtTgt = e.target;
    evtTgt.parentNode.parentNode.removeChild(evtTgt.parentNode);
  }
}

Let’s go through the above code and look at what’s happening.

First, we display a prompt asking the user to name their clip.

Next, we create an HTML structure like the following, inserting it into our clip container, which is an <article> element.

<article class="clip">
  <audio controls></audio>
  <p>_your clip name_</p>
  <button>Delete</button>
</article>

After that, we create a combined Blob out of the recorded audio chunks, and create an object URL pointing to it, using window.URL.createObjectURL(blob). We then set the value of the <audio> element’s src attribute to the object URL, so that when the play button is pressed on the audio player, it will play the Blob.

Finally, we set an onclick handler on the delete button to be a function that deletes the whole clip HTML structure.

So that’s basically it — we have a rough and ready dictaphone. Have fun recording those Christmas jingles! As a reminder, you can find the source code, and see it running live, on the MDN GitHub.

This article is based on Using the MediaStream Recording API by Mozilla Contributors, and is licensed under CC-BY-SA 2.5.

About the author

Chris Mills manages the MDN web docs writers’ team at Mozilla, which involves spreadsheets, meetings, writing docs and demos about open web technologies, and occasional tech talks at conferences and universities. He used to work for Opera and W3C, and enjoys playing heavy metal drums and drinking good beer.

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