Journal tags: attributes

It’s been almost two years since I added audio playback on The Session. The interface is quite straightforward. For any tune setting, there’s a button that says “play audio”. When you press that button, audio plays and the button’s text changes to “pause audio.”

By updating the button’s text like this, I’m updating the button’s accessible name. In other situations, where the button text doesn’t change, you can indicate whether a button is active or not by toggling the aria-pressed attribute. I’ve been doing that on the “share” buttons that act as the interface for a progressive disclosure. The label on the button—“share”—doesn’t change when the button is pressed. For that kind of progressive disclosure pattern, the button also has an aria-controls and aria-expanded attribute.

From all the advice I’ve read about button states, you should either update the accessible name or change the aria-pressed attribute, but not both. That would lead to the confusing situation of having a button labelled “pause audio” as having a state of “pressed” when in fact the audio is playing.

That was all fine until I recently added some more functionality to The Session. As well as being able to play back audio, you can now adjust the tempo of the playback speed. The interface element for this is a slider, input type="range".

But this means that the “play audio” button now does two things. It plays the audio, but it also acts as a progressive disclosure control, revealing the tempo slider. The button is simultaneously a push button for playing and pausing music, and a toggle button for showing and hiding another interface element.

So should I be toggling the aria-pressed attribute now, even though the accessible name is changing? Or is it enough to have the relationship defined by aria-controls and the state defined by aria-expanded?

Based on past experience, my gut feeling is that I’m probably using too much ARIA. Maybe it’s an anti-pattern to use both aria-expanded and aria-pressed on a progressive disclosure control.

I’m kind of rubber-ducking here, and now that I’ve written down what I’m thinking, I’m pretty sure I’m going to remove the toggling of aria-pressed in any situation where I’m already toggling aria-expanded.

What I really need to do is enlist the help of actual screen reader users. There are a number of members of The Session who use screen readers. I should get in touch and see if the new functionality makes sense to them.

I wrote a little something recently about using ARIA attributes as selectors in CSS. For me, one of the advantages is that because ARIA attributes are generally added via JavaScript, the corresponding CSS rules won’t kick in if something goes wrong with the JavaScript:

Generally, ARIA attributes—like aria-hidden—are added by JavaScript at runtime (rather than being hard-coded in the HTML).

But there’s one instance where I actually put the ARIA attribute directly in the HTML that gets sent from the server: aria-live.

If you’re not familiar with it, aria-live is extremely useful if you’ve got any dynamic updates on your page—via Ajax, for example. Let’s say you’ve got a bit of your site where filtered results will show up. Slap an aria-live attribute on there with a value of “polite”:

<div aria-live="polite">
...dynamic content gets inserted here
</div>

You could instead provide a value of “assertive”, but you almost certainly don’t want to do that—it can be quite rude.

Anyway, on the face it, this looks like exactly the kind of ARIA attribute that should be added with JavaScript. After all, if there’s no JavaScript, there’ll be no dynamic updates.

But I picked up a handy lesson from Ire’s excellent post on using aria-live:

Assistive technology will initially scan the document for instances of the aria-live attribute and keep track of elements that include it. This means that, if we want to notify users of a change within an element, we need to include the attribute in the original markup.

Good to know!

Sara tweeted something recently that resonated with me:

Also, Pro Tip: Using ARIA attributes as CSS hooks ensures your component will only look (and/or function) properly if said attributes are used in the HTML, which, in turn, ensures that they will always be added (otherwise, the component will obv. be broken)

Yes! I didn’t mention it when I wrote about accessible interactions but this is my preferred way of hooking up CSS and JavaScript interactions. Here’s old Codepen where you can see it in action:

[aria-hidden='true'] {
  display: none;
}

In order for the functionality to work for everyone—screen reader users or not—I have to make sure that I’m toggling the value of aria-hidden in my JavaScript.

There’s another advantage to this technique. Generally, ARIA attributes—like aria-hidden—are added by JavaScript at runtime (rather than being hard-coded in the HTML). If something goes wrong with the JavaScript, the aria-hidden value isn’t set to “true”, which means that the CSS never kicks in. So the default state is for content to be displayed. There’s no assumption that the JavaScript has to work in order for the CSS to make sense.

It’s almost as though accessibility and progressive enhancement are connected somehow…

Making the Clearleft podcast is a lot of fun. Making the website for the Clearleft podcast was also fun.

Design wise, it’s a riff on the main Clearleft site in terms of typography and general layout. On the development side, it was an opportunity to try out an exciting tech stack. The workflow goes something like this:

• Open a text editor and type out HTML and CSS.

Comparing this to other workflows I’ve used in the past, this is definitely the most productive way of working. Some stats:

• Time spent setting up build tools: 00:00
• Time spent wrangling the pipeline to do exactly what you want: 00:00
• Time spent trying to get the damn build tools to work again when you return to the project after leaving it alone for more than a few months: 00:00:00

I have some files. Some images, three font files, a few pages of HTML, one RSS feed, one style sheet, and one minimal service worker script. I don’t need a web server to do anything more than serve up those files. No need for any dynamic server-side processing.

I guess this is JAMstack. Though, given that the J stands for JavaScript, the A stands for APIs, and I’m not using either, technically it’s Mstack.

Netlify suits my hosting needs nicely. It also provides the added benefit that, should I need to update my CSS, I don’t need to add a query string or anything to the link elements in the HTML that point to the style sheet: Netlify does cache invalidation for you!

The mp3 files of the actual podcast episodes are stored on S3. I link to those mp3 files from enclosure elements in the RSS feed, which is what makes it a podcast. I also point to the mp3 files from audio elements on the individual episode pages—just above the transcript of each episode. Here’s the page for the most recent episode.

I also want people to be able to download the mp3 file directly if they want (or if they want to huffduff an episode). So I provide a link to the mp3 file with a good ol’-fashioned a element with an href attribute.

I throw in one more attribute on that link. The download attribute tells the browser that the URL in the href attribute should be downloaded instead of visited. If you give a value for the download attribute, it will over-ride the file name:

<a href="/files/ugly-file-name.xyz" download="nice-file-name.xyz">download</a>

Or you can use it as a Boolean attribute without any value if you’re happy with the file name:

<a href="/files/nice-file-name.xyz" download>download</a>

There’s one catch though. The download attribute only works for files on the same origin. That’s an issue for me. My site is podcast.clearleft.com but my audio files are hosted on clearleft-audio.s3.amazonaws.com—the download attribute will be ignored and the mp3 files will play in the browser instead of downloading.

Trys pointed me to the solution. It turns out that Netlify can do some server-side processing. It can do redirects.

I added a file called _redirects to the root of my project. It contains one line:

/download/*  https://clearleft-audio.s3.amazonaws.com/podcast/:splat  200

That says that any URLs beginning with /download/ should redirect to clearleft-audio.s3.amazonaws.com/podcast/. Everything after the closing slash is captured with that wild card asterisk. That’s then passed along to the redirect URL as :splat. That’s a new one on me. I hadn’t come across that terminology, but as someone who can never remember the syntax of regular expressions, it works for me.

Oh, and the 200at the end is the status code: okay.

Now I can use this /download/ path in my link:

<a href="/download/season01episode06.mp3" download>Download mp3</a>

Because this URL on the same origin, the download attribute works just fine.