Here are some notes on the topic of accessibility that I took while researching the subject from the perspective of a developer.
When you first start looking into accessibility (or a11y to save on keystrokes) you may think, as I did, that it is a very hard, vague problem that you know you should probably deal with at some point, but somehow there’s always other stuff to do first. Like making the UI look pretty and slick - that always seems to be so much more gratifying.
But as it turns out, a11y is not all that hard to think about, or to take into account while you’re developing. And if you do everything right, it will not only make your app more pleasing to use for people with disabilities, it will enhance the experience for everyone.
The very first thing I suggest you do is watch the Web Accessibility Perspectives videos on Youtube. They were made by the W3C Web Accessibility Initiative and do a very good job of conveying not just the challenges faced by people with disabilities when navigating the web, but also how solving these problems makes your webapp more pleasant to use even for people without disabilities.
Also, reading the Stories of Web Users on the W3C WAI website can be a good first step. These will further expand your understanding of the kinds of disabilities people deal with, and how these affect how people interact with webpages.
Now that you know your audience, all you need to know is what to do, and what not to do, to make sure everyone can enjoy you app. It’s really quite simple when you think about it. There’s two rules, one for input and one for output:
- Make sure all input methods are fully supported. Users should be able to access every part of your application with just a keyboard without a mouse, with only touch and on-screen keyboards, etc..
- Make sure that all important information is conveyed as clearly readable text. So no critical information in images without alt, no graphical structuring of your content unless that structure is also in the markup, sufficient contrast, etc..
Simple isn’t it? And you thought a11y was too hard a topic…
I’ll give a few more detailed notes on certain topics. After that, I have a list of handy resources for you to use to do the good work of making the entire web accessible.
Keyboard navigation is used by people who can’t or won’t use a mouse, e.g. someone with a repetitive strain injury. It’s easy to forget to test your webapp with only keyboard navigation, given how often we devs just click through the UI to test it.
One gotcha that I’ve fallen into a few times while developing an
<a> element without an
href can’t be
reached by pressing
Tab. So either add
(tabindex higher than 0 breaks the element out of the natural tab order
and is discouraged).
For best results: Structure your underlying source code so that the reading/navigation order is correct. Then, if necessary, use CSS to control the visual presentation of the elements on your page. Do not use tabindex values of 1 or greater to change the default keyboard navigation order. – WebAIM: Keyboard Accessibility
- WebAIM: Keyboard Accessibility
- WebAIM: Links and Hypertext
HTML5 introduced a number of new ‘semantic’ tags like
<main> that carry more information about document structure than your
<span>. Assistive technology, like screenreaders,
can use this information to ease navigation. Plus, it’s good for your
Not all assistive technology works consistently with all these new elements, or even supports them yet. The Paciello Group publishes Aural UI of the Elements of HTML which tells you what popular screenreader products do with every HTML tag (though it’s a work in progress).
You may have heard of ARIA attributes, or seen them in example HTML code
on the web. The ARIA spec was
published in 2014. ARIA attributes can help you to explain what kind of
UI-element a given HTML fulfils, if it’s not obvious. So if you use a
<button> (you should) you’re done, but if you insist on using a
<div> instead, you need to add a lot of additional information like
role="button" aria-pressed="false" to make sure everyone understands
what you’re trying to do here (also you need to make sure your
tabindex - honestly just use a
There’s some overlap between ARIA and the new elements presented by HTML5, but not everything ARIA does can be accomplished with HTML5.
- W3C: WAI ARIA Authoring Practices
- W3C: The Roles Model
- WebAIM: ARIA
- Heydon works: Practical ARIA examples
- Terrill Thompson: ARIA Live Region Test
Make sure information in images, videos and other non-text media has a
text-equivalent somewhere in your document. Usually this means writing
alt attribute, or
aria-label. Note however, that although the
alt attribute is required for images, it is sometimes better to leave
them empty. You should definitely read
WebAIM’s article on alt-text -
it’s an eye-opener.
Color is usually something the designer should concern themselves with. In case that is you however, or you want to teach your designer about a11y, here are some notes:
Don’t convey important information only through color - not everybody will be able to perceive it. Use some text, image or icon to convey the same information.
Also check how your design looks to people with different forms of
color-blindness (that’s right, there’s more than one kind). You can
run screenshots or designs through
Vischeck, but most modern image
editors like photoshop will also have an option somewhere to view the
image in the editor like a color-blind person would see it. Check the
Also make sure you’re always using plenty of contrast between text and background, to maximize readability. Plenty of tools can check whether you’re using enough contrast, like e.g. the WebAIM contrastchecker.
- WebAIM Articles
- The Paciello Group blog
- Google: Introduction to Web Accessibility course
- W3C: Tips on Developing for Web Accessibility
- WCAG 2.0 Quick Ref - principles - At a glance