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Web Accessibility Tips and Tricks

The following accessibility tips and tricks address some technical ways to build accessible web pages. There are disagreements within assistive technologies on how to handle the WAI-ARIA specifications. There are many opinions on how to build accessible web pages and the best method to use. The following tips and tricks are how I managed to create accessible web pages that work on most modern assistive technologies.

Different Methods of Navigating a Page

  • Mouse users
  • Touch-screen users
    • devices like a phone/tablet, interacts with the screen directly
    • tappable areas should be large enough (at least 32px x 32px)
  • Keyboard navigation
    • uses keyboard to navigate the page, mostly through the Tab key
    • usually navigating between interactive elements like text inputs, buttons, etc...
  • Screen reader
    • assistive technology that reads the page
    • offers a "virtual cursor" where it highlights areas on the page
    • navigates page using special keyboard keys

When building a feature consider how it can be navigated through multiple mediums.

For example: a common pattern is to use the mouse over state to reveal a menu. That sort of functionality works well for mouse users, but it's almost inaccessible by touch/keyboard/screen readers.

Semantic HTML

Semantic HTML is the foundation of accessibility in a web application. Using the various HTML elements to reinforce the meaning of information in our websites will often give us accessibility for free.

Lists

Any time there is content that would benefit from announcing how many items are there, use a list.

<!-- bad -->
<div>
  <div>Drums</div>
  <div>Drumsticks</div>
</div>

Announcement: Drums. Drumsticks.

<!-- good -->
<ul>
  <li>Drums</li>
  <li>Drumsticks</li>
</ul>

Announcement: list 2 items, Drums, 1 of 2. Drumsticks, 2 of 2, end of list.

Links and Buttons

Non-interactive elements like div with click listeners are not recognized by screen readers and will be skipped.

  • If there is a url, use <a href="url">
  • If there is no url and clicking on it triggers some action on a page, use a <button>
<!-- bad -->
<div onclick="handleClick()">not be detected as interactive element by screen reader/keyboard</div>

Announcement: will not be announced as an interactive element.

<!-- good -->
<a href="https://example.com">learn more about drums</a>

Announcement: link, learn more about drums

<!-- good -->
<button onclick="handleClick()">learn more about drums</button>

Announcement: learn more about drums, button

Landmarks

Using the correct landmark elements helps assistive technologies navigate the page more efficiently. See full list of available landmarks in HTML5

<!-- bad -->
<div class="sidebar">My sidebar</div>
<div class="main-content">My content</div>
<!-- good -->
<aside class="sidebar">My sidebar</aside>

Announcement: complementary, My sidebar

<!-- good -->
<main class="main-content">My content</main>

Announcement: main, My content

Navigation

<!-- bad -->
<div class="navigation">
  <a href="https://example.com">Example</a>
</div>

Announcement: link, Example

<!-- good -->
<nav class="navigation">
  <a href="https://example.com">Example</a>
</nav>

Announcement: navigation. link, Example. end of navigation

<!-- better -->
<nav class="navigation">
  <ul aria-label="About our company">
    <li><a href="https://example.com">Example</a></li>
  </ul>
</nav>

Announcement: navigation. list About our company 1 item. link, Example. end of navigation

The role attribute

Most of the semantic HTML elements can be expressed as non-standard elements (ie. <div>, <span>, etc...) elements with a specific role attribute. However, more often than not, screen readers don't handle these "mocked" elements the same way. Which leads one to add additional functionality (keyboard shortcuts, announcements) to get the same behavior as a semantic element.

Rule of thumb: if there is a semantic element for the purpose, use a semantic element.

Providing additional context

There are many instances in modern user interface design where the content and styling around the call to action provides the context for the label in the call to action.

Some ways assistive technologies navigate a page is by reciting content on the page, like all links in a page. Screen readers will not describe the styling surrounding the entity they are reading. This poses a problem when there are many links that don't have unique labels.

For example: Consider a page where there are many links that say "View more" and nothing else. When screen reader users recite all links on the page, they won't fully understand the context for the "view more" link. Providing additional context via one of the methods below can help.

CSS hidden text

We can provide additional context to a label without making it visible. It keeps the design tidy as designers intended and makes it more accessible to assistive technologies.

<a href="https://example.com">View more <span class="visually-hidden">products in Healthy Snacks</span></a>

Announcement: link, View more products in Healthy Snacks

The visually-hidden css class moves the content out of the view so visual users will not see it, but screen readers will.

The visually-hidden css declaration can be seen below:

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

aria-label

The aria-label property allows us to override what the screen reader would normally announce.

<a href="/product/chocolate" aria-label="Add chocolate to cart">Add to Cart</a>

Announcement: link, Add chocolate to cart

aria-describedby and aria-labelledby

The following two attributes of providing additional context have inconsistent behavior among assistive technologies. Consider using aria-label or the hidden text approach demonstrated in the section above.

The aria-describedby property allows us to declare multiple element ids that provide additional details to the element's label.

<div id="product-title">Chocolate</div>
<a href="/product/chocolate" aria-describedby="product-title">Add to Cart</a>

Announcement: Add to Cart, Chocolate

aria-describedby will announce something like: "Add to cart, Chocolate"

The aria-labelledby attribute allows us to declare multiple element ids that compose the label.

<div id="myBillingId">Billing</div>

<div>
    <div id="myNameId">Name</div>
    <input type="text" aria-labelledby="myBillingId myNameId"/>
</div>

Announcement on the input: Billing Name, edit text

Hiding Elements

Sometimes we have certain things that we do not want to make available to screen readers because that same information is accessible elsewhere. To hide elements from screen readers use the aria-hidden attribute, but it will still be visually rendered.

<div aria-hidden="true">
  The information in here will be visible, but not accessible via screen readers.
  <p>Children will also be hidden</p>
</div>

Using css's display: none; property will hide it visually and from screen readers.

Images

All images that provide context to the page should have thoughtful descriptions.

Imagine you have closed your eyes and have never seen the image before:

  • How would someone describe the image to you?
  • What are the important bits to help provide context to the page?
  • Avoid using words like: "image", "illustration", "picture", etc... since the user will know they are looking at a picture.

Inline Images

Any image that uses the <img> should have an alt property. If the image doesn't provide context to the page and is only there to make the page look pretty, the alt can be an empty string. If the image provides additional context to the page, it needs a thoughtful description.

<img src="" alt="" />

Background Images

Most background images are used for decoration only and do not need alternate text. However, sometimes background images include important information and/or provide context. Consider using a hidden div that contains a description of the image.

<div style="background-image: url(...)">
  <span class="visually-hidden">description of background image</span>
</div>

Alternatively, refactor the code to use <img> tags.

Inline SVG

Hide the svg via aria-hidden="true" and add a visually hidden element that describes it.

<span class="visually-hidden">description of svg</span>
<svg aria-hidden="true"></svg>

There are other approaches to make inline SVGs more accessible but they aren't widely supported:

  1. Adding role="img" and aria-label="..." to the <svg> node
  2. Adding a <title> or <desc> node inside of the svg that describes the image and set an id attribute to each. Then add aria-labelledby to the svg.
<svg role="img" aria-labelledby="svg-title svg-desc">
  <desc id="svg-desc">drumsticks placed on top of a snare drum</desc>
</svg>

Announcement: drumsticks placed on top of a snare drum, image

Input Labels

Each input should have a <label> associated with it:

<label for="firstname">First name:</label>
<input type="text" name="firstname" id="firstname">

Announcement: First name, edit text

Sometimes we don't want to visually display the <label> so we can visually hide the element using our previously described visually-hidden class:

<label for="lastname" class="visually-hidden">Last name:</label>
<input type="text" name="lastname" id="lastname">

Announcement: Last name, edit text

Input Validation

Input are often given different styling to denote invalid input. This styling may not be obvious to assistive technologies. Instructing screen readers that a specific input is invalid can be done via the aria-invalid attribute.

<input aria-invalid="true" />

Announcement: invalid data, edit text

There are exceptions where the inputs are styled as visually disabled and they don't have the disabled attribute declared. Assistive technologies wouldn't announce the disabled styling so the disabled state should be indicated using the aria-disabled attribute.

For example: a button needs to be shown as disabled and it should still be clickable. Maybe clicking on the disabled button triggers a validation announcement.

<button aria-disabled="true" class="button--disabled">Save</button>

Announcement: Save, dimmed, button

Alerts

The web pages might want to inform the user that something changed on the page, that can be done with specific role values.

There are many types of alerts and live regions

<p role="alert">There was an error saving your changes</p>

Announcement: There was an error saving your changes

Live Regions

Javascript offers the ability to dynamically change parts of the page without reloading the page. Screen readers will not pick up those changes to the page unless that area is marked as a live region. Instructing screen readers to watch these regions can be done with the aria-live attribute.

<div id="results-count" aria-live="polite"></div>
function updateResultsCount(count, searchTerm) {
  document.getElementById("results-count").innerText = `Found ${count} results for search term: ${searchTerm}`
}

updateResultsCount(10, "apple")

Announcement: Found 10 results for search term: apple

Beware that if you trigger multiple announcements that contain the same message, some screen readers only announce the first one and ignore subsequent ones. To avoid this announced-once issue, please ensure that each alert message is different.

Beware that the container that has aria-live must exist on the DOM before the content within is modified. If aria-live container is added along with new content it will not be picked up by some screen readers.

A related attribute is aria-atomic which indicates to the screen reader whether it should announce:

  • the entire block when anything changes, or
  • the individual change by itself

Collapsible/Expandable Content

A common design pattern is to have a button that reveals some section, like an accordion. The button that performs the action of revealing a section should be annotated with:

  • aria-haspopup to indicate that the button reveals additional content when interacted.
  • aria-expanded to indicate the expanded status of the content
<!-- collapsed state -->
<button aria-haspopup="true" aria-expanded="false">Learn more about foobar</button>
<div class="collapsed"></div>

Announcement: learn more about foobar, collapsed, pop-up button

<!-- expanded state -->
<button aria-haspopup="true" aria-expanded="true">Learn more about foobar</button>
<div class="expanded">Lorem ipsum...</div>

Announcement: learn more about foobar, expanded, pop-up button

Focus

There will be scenario where the focus need to be moved to a specific area on the page, some of those reasons may be:

  • Moving the focus to the invalid input
  • Moving the focus to a newly added element
  • New search results were loaded in an infinite scroll list

Moving the focus to an input is easy with javascript via $input.focus() where $input represents the DOMElement (input, button, textarea, etc...).

It gets a bit more challenging when the focus needs to be moved to a non-interactive component like a <div>.

The simplest way is to add the tabindex attribute to that destination element.

<div tabindex="-1">my content here</div>

This approach presents a few problems:

  • A non-interactive element gets the focused outline (which can be disabled via css outline: 0)
  • It may be read out loud which may not be a desired behavior

A way to move the focus, but not force the screen reader to read it outloud is to create an empty component that can receive focus. Then we can focus on that element and the blur out of it. That will effectively reset the focus to below the empty component.

<a class="visually-hidden" tabindex="-1" id="resetFocus"></a>
<div tabindex="-1">my content here</div>
const resetFocusAnchor = document.getElementById("resetFocus");
resetFocusAnchor.focus();
resetFocusAnchor.blur();

By following this approach, the focus will be moved after the <a> so be primed for the next Tab keypress.

Beware that moving focus is only effective for keyboard navigation. The screen reader virtual cursor will not be impacted by this approach.

Layout and the Tab Order

We can specify the tabindex of each element in a page by assigning a number that indicates their tab order. However, that approach is hard to maintain, especially in a dynamic page.

A more forgiving way is to let the browser dictate the tab order. The tab order often follows the html structure:

<a href="https://example.com/1">first selected</a>
<a href="https://example.com/2">second selected</a>
<a href="https://example.com/3">third selected</a>

Designs are sometimes complex and there are elements on the page that are declared far apart from each other, but appear visually together (usually via css absolute positioning). Consider the following example: this is a product listing that uses css to move the "see reviews" right below the title.

<div class="product">
  <a href="#">Chocolate Pretzel</a>
  <div class="description">
    Enjoy the combination of salty, 
    crunchy pretzels and peanuts with sweet, 
    rich, chocolaty flavor in these snack bars.
    <a href="#">Read more</a>
  </div>
  <a href="#" class="reviews">See reviews</a>
</div>
.product {
  position: relative;
}
.reviews {
  position: absolute;
  top: 15px;
}
.description {
  margin-top: 20px;
}

This causes the tab order to feel unnatural because the tab order will go from the product title to "read more" in the description and finally land on "see reviews". Visually the expectation would be to go from product title, see reviews, and finally read more.

Consider grouping related elements together to maintain a sensible tab order:

<div class="product">
 <a href="#">Chocolate Pretzel</a>
 <a href="#">See reviews</a>
 <div>
   Enjoy the combination of salty, 
   crunchy pretzels and peanuts with sweet, 
   rich, chocolaty flavor in these snack bars.
   <a href="#">Read more</a>
 </div>
</div>

Tooling

  • eslint-plugin-jsx-a11y - Static AST checker for accessibility rules on JSX elements.
    • informs about missing properties and/or their values
  • Chrome Lighthouse - Audits for performance, accessibility, progressive web apps, SEO and more.
    • helps
  • axe DevTools - Audits for accessibility issues