Tags: disclosure

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 while back about making an accessible progressive disclosure pattern. It’s very basic—just a few ARIA properties and a bit of JavaScript sprinkled onto some basic HTML. The HTML contains a button element that toggles the aria-hidden property on a chunk of markup.

Earlier this week I had a chance to hang out with accessibility experts Derek Featherstone and Devon Persing so I took the opportunity to pepper them with questions about this pattern. My main question was “Should I automatically focus the toggled content?”

Derek’s response was very perceptive. He wanted to know why I was using a button. Good question. When you think about it, what I’m doing is pointing from one element to another. On the web, we point with links.

There are no hard’n’fast rules about this kind of thing, but as Derek put it, it helps to think about whether the action involves controlling something (use a button) or taking the user somewhere (use a link). At first glance, the progressive disclosure pattern seems to be about controlling something—toggling the appearance of another element. But if I’m questioning whether to automatically focus that element, then really I’m asking whether I want to take the user to that place in the document—in other words, linking to it.

I decided to update the markup. Here’s what I had before:

<button aria-controls="content">Reveal</button>
<div id="content"></div>

Here’s what I have now:

<a href="#content" aria-controls="content">Reveal</a>
<div id="content"></div>

The logic in the JavaScript remains exactly the same:

1. Find any elements that have an aria-controls attribute (these were buttons, now they’re links).
2. Grab the value of that aria-controls attribute (an ID).
3. Hide the element with that ID by applying aria-hidden="true" and make that element focusable by adding tabindex="-1".
4. Set aria-expanded="false" on the associated link (this attribute can be a bit confusing—it doesn’t mean that this element is not expanded; it means the element it controls is not expanded).
5. Listen for click events on those links.
6. Toggle the aria-hidden and aria-expanded when there’s a click event.
7. When aria-hidden is set to false on an element (thereby revealing it), focus that element.

You can see it in action on CodePen.

See the Pen Accessible toggle (link) by Jeremy Keith (@adactio) on CodePen.

Over on The Session I have a few instances of a progressive disclosure pattern. It’s just your basic show/hide toggle: click on a button; see some more content. For example, there’s a “download” button for every tune that displays options to download the tune in different formats (ABC and midi).

To begin with, I was using the :checked pseudo-class pattern that Charlotte has documented so well. I really like that pattern. It feels nice and straightforward. But then I got some feedback from someone using the site:

the link for midi files is no longer coming up on the tune pages. I am blind so I rely on the midi’s when finding tunes for my students.

I wrote back saying the link to download midi files was revealed by the “download” option. The response:

Excellent. I have it now, I was just looking for the midi button which wasn’t there. the actual download button doesn’t read as a button under each version of the tune but now I know it’s there I know what I am doing. I am using the JAWS screen reader.

This was just one person …one person who took the time to write to me. What about other screen reader users?

I dabbled around with adding role="button" to the checkbox or the label, but that felt really icky (contradicting the inherent role of those elements) and it didn’t seem to make much difference anyway.

I decided to refactor the progressive disclosure to use JavaScript instead just CSS. I wanted to make sure that accessibility was built into the functionality, rather than just bolted on. That’s why code I’ve written doesn’t rely on the buttons having a particular class value; instead the buttons must have an aria-controls attribute that associates the button with the element it toggles (in much the same way that a for attribute associates a label with a form field).

Here’s the logic:

1. Find any elements that have an aria-controls attribute (these should be buttons).
2. Grab the value of that aria-controls attribute (an ID).
3. Hide the element with that ID by applying aria-hidden="true" and make that element focusable by adding tabindex="-1".
4. Set aria-expanded="false" on the associated button (this attribute can be a bit confusing—it doesn’t mean that this element is not expanded; it means the element it controls is not expanded).
5. Listen for click events on those buttons.
6. Toggle the aria-hidden and aria-expanded when there’s a click event.
7. When aria-hidden is set to false on an element (thereby revealing it), focus that element.

You can see it action on CodePen.

I’m still playing around with this. I think the :focus styles are probably far too subtle right now—see this excellent presentation from Laura Palmaro for more on that. I’m also not sure if the revealed content should automatically take focus. I’ll see if I can get some feedback from people on The Session using screen readers—there’s quite a few of them.

Feel free to use my code but you might want to check out Jason’s code to do the same thing—his is bound to be nicer to work with.

Update: In response to this discussion, I’ve decided not to automatically focus the expanded content.