Tags: a11y

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An nth-letter selector in CSS

Variable fonts are a very exciting and powerful new addition to the toolbox of web design. They was very much at the centre of discussion at this year’s Ampersand conference.

A lot of the demonstrations of the power of variable fonts are showing how it can be used to make letter-by-letter adjustments. The Ampersand website itself does this with the logo. See also: the brilliant demos by Mandy. It’s getting to the point where logotypes can be sculpted and adjusted just-so using CSS and raw text—no images required.

I find this to be thrilling, but there’s a fly in the ointment. In order to style something in CSS, you need a selector to target it. If you’re going to style individual letters, you need to wrap each one in an HTML element so that you can then select it in CSS.

For the Ampersand logo, we had to wrap each letter in a span (and then, becuase that might cause each letter to be read out individually instead of all of them as a single word, we applied some ARIA shenanigans to the containing element). There’s even a JavaScript library—Splitting.js—that will do this for you.

But if the whole point of using HTML is that the content is accessible, copyable, and pastable, isn’t a bit of a shame that we then compromise the markup—and the accessibility—by wrapping individual letters in presentational tags?

What if there were an ::nth-letter selector in CSS?

There’s some prior art here. We’ve already got ::first-letter (and now the initial-letter property or whatever it ends up being called). If we can target the first letter in a piece of text, why not the second, or third, or nth?

It raises some questions. What constitutes a letter? Would it be better if we talked about ::first-character, ::initial-character, ::nth-character, and so on?

Even then, there are some tricksy things to figure out. What’s the third character in this piece of markup?

<p>AB<span>CD</span>EF</p>

Is it “C”, becuase that’s the third character regardless of nesting? Or is it “E”, becuase techically that’s the third character token that’s a direct child of the parent element?

I imagine that implementing ::nth-letter (or ::nth-character) would be quite complex so there would probably be very little appetite for it from browser makers. But it doesn’t seem as problematic as some selectors we’ve already got.

Take ::first-line, for example. That violates one of the biggest issues in adding new CSS selectors: it’s a selector that depends on layout.

Think about it. The browser has to first calculate how many characters are in the first line of an element (like, say, a paragraph). Having figured that out, the browser can then apply the styles declared in the ::first-line selector. But those styles may involve font sizing updates that changes the number of characters in the first line. Paradox!

(Technically, only a subset of CSS of properties can be applied to ::first-line, but that subset includes font-size so the paradox remains.)

I checked to see if ::first-line was included in one of my favourite documents: Incomplete List of Mistakes in the Design of CSS. It isn’t.

So compared to the logic-bending paradoxes of ::first-line, an ::nth-letter selector would be relatively straightforward. But that in itself isn’t a good enough reason for it to exist. As the CSS Working Group FAQs say:

The fact that we’ve made one mistake isn’t an argument for repeating the mistake.

A new selector needs to solve specific use cases. I would argue that all the letter-by-letter uses of variable fonts that we’re seeing demonstrate the use cases, and the number of these examples is only going to increase. The very fact that JavaScript libraries exist to solve this problem shows that there’s a need here (and we’ve seen the pattern of common JavaScript use-cases ending up in CSS before—rollovers, animation, etc.).

Now, I know that browser makers would like us to figure out how proposed CSS features should work by polyfilling a solution with Houdini. But would that work for a selector? I don’t know much about Houdini so I asked Una. She pointed me to a proposal by Greg and Tab for a full-on parser in Houdini. But that’s a loooong way off. Until then, we must petition our case to the browser gods.

This is not a new suggestion.

Anne Van Kesteren proposed ::nth-letter way back in 2003:

While I’m talking about CSS, I would also like to have ::nth-line(n), ::nth-letter(n) and ::nth-word(n), any thoughts?

Trent called for ::nth-letter in January 2011:

I think this would be the ideal solution from a web designer’s perspective. No javascript would be required, and 100% of the styling would be handled right where it should be—in the CSS.

Chris repeated the call in October of 2011:

Of all of these “new” selectors, ::nth-letter is likely the most useful.

In 2012, Bram linked to a blog post (now unavailable) from Adobe indicating that they were working on ::nth-letter for Webkit. That was the last anyone’s seen of this elusive pseudo-element.

In 2013, Chris (again) included ::nth-letter in his wishlist for CSS. So say we all.

Marking up help text in forms

Zoe asked a question on Twitter recently:

‘Sfunny—I had been pondering this exact question. In fact, I threw a CodePen together a couple of weeks ago.

Visually, both examples look the same; there’s a label, then a form field, then some extra text (in this case, a validation message).

The first example puts the validation message in an em element inside the label text itself, so I know it won’t be missed by a screen reader—I think I first learned this technique from Derek many years ago.

<div class="first error example">
 <label for="firstemail">Email
<em class="message">must include the @ symbol</em>
 </label>
 <input type="email" id="firstemail" placeholder="e.g. you@example.com">
</div>

The second example puts the validation message after the form field, but uses aria-describedby to explicitly associate that message with the form field—this means the message should be read after the form field.

<div class="second error example">
 <label for="secondemail">Email</label>
 <input type="email" id="secondemail" placeholder="e.g. you@example.com" aria-describedby="seconderror">
 <em class="message" id="seconderror">must include the @ symbol</em>
</div>

In both cases, the validation message won’t be missed by screen readers, although there’s a slight difference in the order in which things get read out. In the first example we get:

  1. Label text,
  2. Validation message,
  3. Form field.

And in the second example we get:

  1. Label text,
  2. Form field,
  3. Validation message.

In this particular example, the ordering in the second example more closely matches the visual representation, although I’m not sure how much of a factor that should be in choosing between the options.

Anyway, I was wondering whether one of these two options is “better” or “worse” than the other. I suspect that there isn’t a hard and fast answer.

Unlabelled search fields

Adam Silver is writing a book on forms—you may be familiar with his previous book on maintainable CSS. In a recent article (that for some reason isn’t on his blog), he looks at markup patterns for search forms and advocates that we should always use a label. I agree. But for some reason, we keep getting handed designs that show unlabelled search forms. And no, a placeholder is not a label.

I had a discussion with Mark about this the other day. The form he was marking up didn’t have a label, but it did have a button with some text that would work as a label:

<input type="search" placeholder="…">
<button type="submit">
Search
</button>

He was wondering if there was a way of using the button’s text as the label. I think there is. Using aria-labelledby like this, the button’s text should be read out before the input field:

<input aria-labelledby="searchtext" type="search" placeholder="…">
<button type="submit" id="searchtext">
Search
</button>

Notice that I say “think” and “should.” It’s one thing to figure out a theoretical solution, but only testing will show whether it actually works.

The W3C’s WAI tutorial on labelling content gives an example that uses aria-label instead:

<input type="text" name="search" aria-label="Search">
<button type="submit">Search</button>

It seems a bit of a shame to me that the label text is duplicated in the button and in the aria-label attribute (and being squirrelled away in an attribute, it runs the risk of metacrap rot). But they know what they’re talking about so there may well be very good reasons to prefer duplicating the value with aria-label rather than pointing to the value with aria-labelledby.

I thought it would be interesting to see how other sites are approaching this pattern—unlabelled search forms are all too common. All the markup examples here have been simplified a bit, removing class attributes and the like…

The BBC’s search form does actually have a label:

<label for="orb-search-q">
Search the BBC
</label>
<input id="orb-search-q" placeholder="Search" type="text">
<button>Search the BBC</button>

But that label is then hidden using CSS:

position: absolute;
height: 1px;
width: 1px;
overflow: hidden;
clip: rect(1px, 1px, 1px, 1px);

That CSS—as pioneered by Snook—ensures that the label is visually hidden but remains accessible to assistive technology. Using something like display: none would hide the label for everyone.

Medium wraps the input (and icon) in a label and then gives the label a title attribute. Like aria-label, a title attribute should be read out by screen readers, but it has the added advantage of also being visible as a tooltip on hover:

<label title="Search Medium">
  <span class="svgIcon"><svg></svg></span>
  <input type="search">
</label>

This is also what Google does on what must be the most visited search form on the web. But the W3C’s WAI tutorial warns against using the title attribute like this:

This approach is generally less reliable and not recommended because some screen readers and assistive technologies do not interpret the title attribute as a replacement for the label element, possibly because the title attribute is often used to provide non-essential information.

Twitter follows the BBC’s pattern of having a label but visually hiding it. They also have some descriptive text for the icon, and that text gets visually hidden too:

<label class="visuallyhidden" for="search-query">Search query</label>
<input id="search-query" placeholder="Search Twitter" type="text">
<span class="search-icon>
  <button type="submit" class="Icon" tabindex="-1">
    <span class="visuallyhidden">Search Twitter</span>
  </button>
</span>

Here’s their CSS for hiding those bits of text—it’s very similar to the BBC’s:

.visuallyhidden {
  border: 0;
  clip: rect(0 0 0 0);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute;
  width: 1px;
}

That’s exactly the CSS recommended in the W3C’s WAI tutorial.

Flickr have gone with the aria-label pattern as recommended in that W3C WAI tutorial:

<input placeholder="Photos, people, or groups" aria-label="Search" type="text">
<input type="submit" value="Search">

Interestingly, neither Twitter or Flickr are using type="search" on the input elements. I’m guessing this is probably because of frustrations with trying to undo the default styles that some browsers apply to input type="search" fields. Seems a shame though.

Instagram also doesn’t use type="search" and makes no attempt to expose any kind of accessible label:

<input type="text" placeholder="Search">
<span class="coreSpriteSearchIcon"></span>

Same with Tumblr:

<input tabindex="1" type="text" name="q" id="search_query" placeholder="Search Tumblr" autocomplete="off" required="required">

…although the search form itself does have role="search" applied to it. Perhaps that helps to mitigate the lack of a clear label?

After that whistle-stop tour of a few of the web’s unlabelled search forms, it looks like the options are:

  • a visually-hidden label element,
  • an aria-label attribute,
  • a title attribute, or
  • associate some text using aria-labelledby.

But that last one needs some testing.

Update: Emil did some testing. Looks like all screen-reader/browser combinations will read the associated text.

Accessible progressive disclosure revisited

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.

Accessible progressive disclosure

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.