Web accessibility for developers

Web accessibility

Websites and apps are perceivable, operable,
and understandable, even if:

• You've got a disability

• You're getting older
• You're limited due to specific circumstances.

About 15% of the world's population lives with some form of disability.

#WeThe15

Belgian population

19% is over the age of 67 in 2024.

Source

Websites and apps

• People want to participate in the digital world regardless of disability.
• Often 'early adopters'.
• This is possible when websites and apps are accessible.

Legislation and standards

European Directive

Directive (EU) 2016/2102 of the european parliament and of the council of 26 October 2016 on the accessibility of the websites and mobile applications of public sector bodies

European Directive

• Websites (as of September 2020) and apps (as of June 2021) by government institutions must be accessible according to the Web Content Accessibility Guidelines 2.1 Level AA.
• Each website or app has an accessibility statement.
• FOD Bosa is responsible for the enforcement, monitoring, and reporting: https://accessibility.belgium.be

WCAG Standard

• 2008: Web Content Accessibility Guidelines 2.0
• 2018: Web Content Accessibility Guidelines 2.1
• 3 levels
• 50 success criteria on level AA
• Technical support guidelines

Accessibility statement

• Which accessibility requirements does the website/app meet?
• How was this tested?
• If there are parts that are inaccessible, what is the temporary alternative?
• How can a user report accessibility issues?
• Which procedure is available to the user if no (adequate) reply to their feedback is given?

How to write an accessibility statement??

Belgium in 2020

Nina has ADHD

Nina has trouble focusing. She's very sensitive to sensory stimuli, and often forgets things.

Distractions

• Slideshows (-/+)
• Animated gifs
• Background video's
• Pop-ups

Pop-ups

Expected vs. Unexpected

Best practices

• Use a pause button to give control to the user
• No autoplay
• Be mindful of background images and other distractions

Jerry is colour blind

Jerry has difficulties telling red and green apart.

8% of all men are colour blind

• Deuteran (green - common)
• Protan (red - rare)
• Tritan (blue - very rare)

Source: We are colorblind

Information about arrivals and departures

The same information with color and text

Pie chart - inaccessible to Jerry

Accessible pie chart

Best practice

Use more than just colour to convey information.

Kadisha has cataract

Vision simulator

Silktide

Kadisha can't read all of the numbers in this table.

Provide sufficient contrast between the text and the background colour.

Contrast for non-text components

• User interface components
• Images necessary to understand content
• Contrast with adjacent colours

Magnification and responsive design

Build responsive websites.

Spam prevention

Most CAPTCHA's are inaccessible: provide accessible alternatives.

Jim has a motor impairment

Jim can't use a mouse.
He uses a headstick and a keyboard, instead.

Try it yourself

• Tab: next interactive element
• Shift + tab: previous interactive element
• Enter: activate link or button
• Spacebar: select checkbox or radio button
• Up and down arrow keys: select list item

Example

Example 1 - visible focus

Try to reach the following pages by using the tab key.

• "At a Glance" on W3C
• Any slideshow article on Dreamland

Example 2 - drop-down menu

Try to expand the main menu without using the mouse.

• Daily Star
• Mozilla Developer Network

Best practice

• Provide visible focus
• All functionalities that can be achieved by using a mouse must work when using a keyboard as well.

Vera has ALS

Switch control

"It took me too long to fill in the form, and it disappeared. Now I'm back in the queue. I'll probably miss out on those concert tickets."

Best practice

Give users enough time to complete their actions.

Caroline has RSI

Repetitive Stress Injury causes Caroline wrist- and shoulder pain. She uses voice recognition software in order to rest her arm and avoid any further injury.

Example

Dragon Naturally Speaking

Caroline can't click on an icon unless she knows its name.

• How icons are ruining interfaces
• The best icon is a text label

Best practice

• Give icons a visible label
• Use meaningful links and alternative texts
• Use structural elements correctly

David is blind

David uses a screenreader and a braille display.

Examples

• Demo
• Graphic links

Want to try for yourself?

Best practice

• Add alternative texts to informative images
• Use proper headings

Tom has reading difficulties

Tom can read simple texts with everyday words.

In the Netherlands, 75% of the texts on public websites correspond to reading level C1, but most of the population has a reading level well below that.

Too difficult

Quality jobs ensure economic independence, foster personal achievement, and offer the best protection against poverty... The commission will improve knowledge of the employment situation of women and men with disabilities, identify challenges, and propose remedies. It will pay particular attention to young people with disabilities in their transition from education to employment. It will address intra-job mobility on the open labour market and in sheltered workshops, through information exchange and mutual learning. It will also address the issue of self employment and quality jobs, including aspects such as working conditions and career advancement ...

Best practices

• Take your audience into account while writing
• Avoid jargon
• Keep texts short
• Use active sentences
• Delete redundant words

Easier

Jobs are important because they protect people from being poor and make sure that people have their own independence.

The European Union plans to:

1. make workplaces more accessible
2. support job training
3. increase access to jobs for people with disabilities

Source Easy to read version of European disability strategy (PDF)

Hilde is deaf

Uncaptioned videos are useless to Hilde.

Subtitles (translation)

Captions for deaf and hard of hearing individuals

Text version/transcript

Best practice

• Add subtitles to videos
• Provide a textual transcript

Why do you use captions?

Bron: close captions for everybody

English isn't my native language. With captions, it's easier to understand and I remember more of the words I'm trying to learn.

When characters are mumbling, or speaking with an unfamiliar accent.

There are many people in one room, all using different screens (competing noise).

I'm watching tv with the volume down because my baby is asleep.

Loud, crunchy snacks.

What can you do?

Focus points according to specific themes

Keyboard accessibility

All functionalities that can be achieved by using a mouse must work when using a keyboard as well.

Put your mouse aside

• Use the tab key to navigate through links, buttons, and forms (MacOs might need extra configuration)
• Links and buttons can be activated with enter
• Form elements can be used with the spacebar or arrows

Basic test

• Can you see the focus outline?
• Can you access everything on the site?
• Is the reading order logical?
• Can you use all features?

Can you see the focus?

When tabbing through a website, can you see the focus outline at all times? (- / +)

Focus style

Don't remove it:

a:focus { outline: none }

Enhance it:

a:focus { color: #fff; background: #00F; }

Can you access everything on the wesite?

Are all links, form fields, and buttons accessible by tab key?

• Not accessible: div onclick
• High risk for errors
• Example: try to reach the button "extra website" on Dilbeek.be
• Always use a href or button

Is the reading order logical?

• Reading/tab order = defined by the order of elements within the source code
• Source code must correspond to visual reading order
• Beware of responsive layout

Exception: cookie banner

• Usually an overlay
• User wants to get rid of the cookie banner as fast as possible
• Place the cookiebanner on top within the source code
• Example -/ +

Can you use all features?

• Can every link be activated with enter?
• Can each radio button be selected with the space bar ?
• Can each button be clicked using the space bar or enter?
• Can each list be navigated with the arrow keys?

Keyboard interaction

• Always works with native HTML: a, button, input, select, list,...
• Custom-made widgets and forms: all accessibility has to be provided by you.
• Use authoring practices to provide accessibility.

Tabindex attribute

• Influences tab order
• Only used in specific situations
• Using the tabindex attribute by Léonie Watson

Tabindex="0"

To make an element reachable with the tab key: use tabindex="0"

When using div or span.

Tabindex="-1"

• Makes an element focusable but not included in the tab order.
• Use JavaScript for focus management (later more).
• Example: to draw attention to errors when filling in a form.

Tabindex="1"

• Use tabindex="1" (and higher numbers) to enforce a specific tabbing order.
• Use sparingly: prone to errors and confusion.
• Especially when you forget elements (negative example)

Also keyboard-related

Skip links

• Useful when navigation is complex
• Use sparingly

Keyboard trap

Make sure the focus doesn't get trapped within an element or compoment, e.g. form or a list

Keyboard shortcuts

When you add shortcuts:

• allow user to turn them off
• allow user to redefine them to their own needs
• make the shortcut available only when the component using it receives focus

Example

• YouTube allows you to pause a video using the letter k
• Shortcut only works when the video is focused, not anywhere else on the webpage
• Why: to avoid overwriting user's pre-existing custom keyboard shortcuts

Links

Good links

• Are visible to everyone
• Have a meaningful link text

Differentiate links and text visually

Why make link texts meaningful?

• Visitors scan links first
• Screenreader users use link lists for navigation
• SEO rewards usage of relevant keywords in link texts

What is a meaningful link text?

• The link text states the link's goal
• Keep it brief
• Consequences are clear: e.g. download pdf, play video, play sound,...

Bad examples

• Click here
• Full URL
• 'Download' without extra information
• 'Brochure' without the title of the document
• <<    <   May 2021   >    >>
• more ...

A link is a promise

• Download this season's TV programme (PDF).
• Listen to interview with minister X
• Download the BBC News app from the Apple Store

Semantics

Use proper HTML tags:

• Headings: h1-h6
• Lists: ul/ol
• Tables: th, caption, tr, th, td
• Regions: header, nav, main, footer

Headings

• Headings are marked as HTML headings
• Big and bold does not equal a heading
• Headings are followed by related content
• Use proper heading levels to create a logical hierarchy

How to check heading levels

• User Web Developer Toolbar
• Choose Outline > Outline Headings
• Check 'Show Element Names When Outlining'
• Headings are now marked, including the heading level

Lists

• No DIY bullets (-, °, *)
• Lists must contain more than 1 item
• Navigations are usually lists

Tables

• Th-elements for table headings
• Caption for legend (if present)
• Example
• Exercise : inspect and correct

HTML5 sectioning elements

• header and footer
• nav for menu and submenu
• main for main content
• article only for sections that can be read independently (don't overdo)

Don't misuse semantic elements

• Don't use h6 to style small paragraphs
• Don't use blockquotes to indent content
• Only use nav for main navigation regions (use sparingly)

Exercise: identify the structure of a page

• Pick a page on a website
• Observe the page without looking at the code
• Identify the landmark regions: header, main, footer, nav
• Identify the headings and their levels

ARIA

Accessible Rich Internet Applications

ARIA

• To make advanced web components accessible
• Extra techniques to satisfy WCAG success criteria
• W3C ARIA Authoring Practices Guide

Assistive technology and semantics

The accessibility tree

Chrome Dev Tools

• The browser creates an accessibility tree based on source code
• Assistive technologies access this information via accessibility API
• Each component has a name, role, state, properties and sometimes a description
• Native HTML elements provide those implicitly

<button>Search</button>

Accessibility tree:

• Role: button
• Name: Search
• State: unselected
• Property: focusable

Accessibility tree:

• Role: /
• Name: /
• State: /
• Property: /

Chrome Developer Tools

ARIA attributes

Change information in the accessibility tree.

ARIA-attributes change semantics

• Their main purpose is to add missing semantics to the accessibility tree.
• Can also modify semantic information.
• Can also delete semantics.

1. Role

• In accessibility tree, each component needs a role.
• If an HTML element exists with the desired role: use it.
• Semantic elements fill the accessibility tree.
• Also the role-attribute defines the role of a component in the accessibility tree.

Good example: tabs widget

• In HTML, there is no semantic element for tab panels.
• They are divs and those have no role in accessibility tree.
• role="tabpanel" completes the accessibility tree.

<div id="tabpanel2" role="tabpanel">

ARIA wins!

• A component can only have one role
• If the component already has an implicit role, the role attribute overwrites it.<

Bad example

<div id="main_nav">
<ul role="navigation">

• The ul element gives the component implicitly the role 'list'
• role="navigation" changes this role to 'navigation'
• Only 1 role possible. ARIA wins! It is no longer a list.
• Screenreader announces navigation section but no list.

Better

<div id="main_nav" role="navigation">
<ul>

Or:

<nav id="main_nav">
<ul>

The role attribute

• Only changes the semantic information in the accessibility tree.
• The role attribute does NOT change
  • Behaviour
  • Properties
  • Appearance

Example

<div role="button">
Search
</div>

No button yet

• Screenreader says "button search" instead of "search".
• But:
  • Can't be reached with tab key
  • Does not look like a button
  • Clicking on it, does nothing

Possible values for role attribute

• Are pre-defined, don't invent them
• Redundancy with HTML elements
• Addition to HTML
• role="presentation"
• role="application"

Redundancy with HTML elements

• role="navigation" versus <nav>
• role="button" versus <button>
• role="checkbox" versus <input type="checkbox">
• ...

Addition to HTML

• tablist, tab, tabpanel
• progressbar
• spinbutton
• ...

Role names can be confusing (read the spec!)

• Don't use role="menu" for a sequence of links: WAI-ARIA menus, and why you should handle them with great care
• Don't use role="grid" for a sortable table
• Don't use role="treeview" for a drop-down menu
• ARIA: The Cause of, and Solution to, All Our Accessibility Problems

Role="presentation" or role="none"

• Removes the role from accessibility tree
• = deletes semantics

Example

News

Becomes this in accessibility tree:

News

But still looks like a heading.

When to use?

• When fixing legacy code with layout tables
• As a compromise in semantic discussions

Role="application"

• Changes the component in the accessibility tree into an application.
• All functionality that assistive technologies provide, is dropped.
• You have to program everything again yourself.
• You must explain the user how the application works.

In practice

• Use extremely rarely
• On a small a container as possible.
• Some roles also trigger aplication mode, e.g. role="dialog"
• role="document" inside an application allows default behaviour again in that container.

Summary

• The role attribute can add missing information to the accessibility tree
• Be careful with overwriting the implicit role.
• role="presentation" deletes the semantic role.
• Role does not modify how it looks like and how it works.

States and properties

• Component in accessibility tree not only has a role, but also a status and properties.
• Can be added or changed with ARIA attributes:
• How to toggle ARIA values with JavaScript

States and properties

Modify existing states or properties in accessibility tree:

• aria-expanded="true" or "false"
• aria-hidden="true" or "false"
• aria-selected="true" or "false"
• ...

Aria-hidden

• aria-hidden="true"removes element from accessibility tree
• The element with aria-hidden="true" remains visible on the screen, but becomes inaccessible to assistive technology
• Do not use for interactive elements

2. Name

• Each component needs a name in the accessibility tree
• Implicit: link text, alt attribute, label of button, etc.
• Explicit: aria-label or aria-labelledby

Example

Aria-label

• Attribute value = text
• If component did not have a name, it will be added
• If component already had a name, it will be replaced

Bad example

Don't overwrite existing name:

<a href="w3.org" 
aria-label="World Wide Web Consortium">
W3C
</a>

• On the screen: W3C
• Screenreader reads: [link] "World Wide Web Consortium"
• Dictation software user speaks: [click] "W3C", but nothing happens

Accessibility tree

Aria-labelledby

• Attribute value = id reference to content that is elsewhere
• Multiple references are possible, separated by spaces

Example

<a role="tab" id="tablist1">Monday</a>
<a role="tab" id="tablist2">Tuesday</a>

<div id="tabpanel1" role="tabpanel" aria-labelledby="tablist1"></div>
<div id="tabpanel2" role="tabpanel" aria-labelledby="tablist2"></div>

Warnings for aria-label(ledby)

• Can only be used for components that have a role (not on div or span)
• Only available in accessibility tree: possible mismatch with information on screen
• Don't forget to translate
• Don't overdo it
• Do not repeat the role

Don't repeat the role

<button aria-label="Search button">

<a href="facebook.com" aria-label="Link to Facebook"></a>

<nav aria-label="Main navigation">

<main aria-label="Main content">

Better

<button aria-label="Search">

<a href="facebook.com" aria-label="Facebook"></a>

<nav> of <nav aria-label="Main">

<main>

3. States and properties

• Component has in accessibility tree also states and properties.
• There are ARIA attributes to add or change them.
• How to toggle ARIA values with JavaScript

Examples

• aria-expanded="true", aria-expanded="false"
• aria-hidden="true", aria-hidden="false"
• aria-checked="true", aria-checked="false"

Aria-hidden

• Aria-hidden="true" deletes component and all its children from accessibility tree
• Remains visible on the screen, but becomes inaccessible for assistive technologies
• Don't use it for interactive elements

Example

<div aria-hidden="true">
This text is visible on the screen but you don't hear it with a screenreader.
</div>

<a href="#" aria-hidden="true">
This link does not work for asssistive technology users.
</a>

4. Description

• A component may also have a description in accessibility tree
• Not the same as a name/label, no risk of overwriting
• Aria-describedby=""
• Value = 1 or multiple id references

Example

<label for="email">e-mail</label>
			<input type="text" name="email" id="email" aria-describedby="error17">
			<p class="error" id="error17">The email address is not valid</p>

Screenreader reads

When focus reaches the edit field with the tab key:

E-mail address, edit field, The email address is not valid.

Usage

• Rarely
• Only on component with semantic role
• Only on components that receive focus, such as links, buttons or form fields.
• Only to be added when text is/becomes visible.

Summary

• Don't use ARIA when HTML can be used
• ARIA attributes only manipulate the accessibility tree; They don't add functionality
• Remember: "No ARIA is better than bad/redundant ARIA"

Support

• Accessibility trees can differ per browser
• Assistive technology is improving, but not perfect
• Users are not used to all or new functionalities

Exercises

<ul role="list">
	

<div class="h2" role="heading" aria-level="2">

<div role="checkbox" aria-checked="true">

<article role="presentation">

<iframe name="google_ads" aria-hidden="true">

What's wrong?

<a href="https://twitter.com">
		<span class="twitter_icon" aria-label="Follow us on Twitter"></span>
		</a>
		

What's wrong?

<label for="tel">Phone number:</label>
		<input type="text id="tel" aria-labelledby="nota" />
		<p id="nota">Please do not include spaces, dashes or periods</p>

Colour & contrast

Use of colour

Don't use colour alone to convey information

body {
	 filter : grayscale(100%);
	}

Sufficient contrast

• Text smaller than 24px: minimum 4,5:1
• Text larger than 24px: minimum 3:1
• Bold text of 18,5px and more: minimum 3:1
• User interface components: minimum 3:1

Icons

Form fields

Colour Contrast Analyser

Tip

Use different shades of the same colour instead of different colours.

Tools

• Colour contrast analyser
• Tanaguru Contrast-Finder
• Accessible color matrix
• Google Chrome Accessibility Developer Tools

Images

Alternative text

• Provide images with an alternative text
• Content depends on:
• image type
• context (informative or decorative)

Decorative images

• Preferably as CSS background image
• <img alt="" />
• Screenreader will ignore both examples
• A link is never decorative

An alt decision tree

Photo's

Describe the image briefly

Graphics and text

Repeat the literal image text in alt text

Can it be done with HTML & CSS?

Avoid images of text

Image as a link

Link goal > image description

Images with complex info

• Map
• Organisation chart
• Diagram
• Infografic

Brief alt text and equal alternative

Example: map

Example: text alternative map

Example: infografic with numbers

CSS background-images

a.twitter:after { 
	 content:url('icon_twitter.png'); 
	}

When they contain information: provide hidden content

	Twitter
	

a.twitter:after { 
	 content:url('icon_twitter.png'); 
	}
	
	.visuallyhidden { 
	 border: 0; 
	 clip: rect(0 0 0 0); 
	 height: 1px; 
	 margin: -1px; 
	 overflow: hidden; 
	 padding: 0; 
	 position: absolute; 
	 width: 1px;
	}

Icon fonts

• Add character using CSS (:before or :after)
• Hide character using aria-hidden="true"
• Decorative: hiding character is enough
• Informative: add an invisible textual alternative

SVG

• Scalable Vector Graphic
• Still some support issues from screenreaders

Bulletproof:

<img src="logo.svg" alt="logo AnySurfer" />
	

Theory, but not always supported

<svg>
<title>brief description</title>
<description>extended description</description>
...
</svg>
	

ARIA: moderate support

<svg role="img" aria-labelledby="title">
 <title id="title">AnySurfer logo</title>
 ...
</svg>
	

SVG within a link: add invisible content

<a href="index.html">
 <span class="visuallyhidden">AnySurfer home page</span>
<svg role="presentation" focusable="false">
...
 </svg>
</a>
	

Or add ARIA-label, e.g. for a button:

<button type="button" aria-label="AnySurfer home page">
 <svg role="presentation" focusable="false">
 ...
 </svg>
 </button>
	

Images on social media

• Facebook (has automated alt text)
• Twitter
• Instagram
• LinkedIn
• Pinterest
• Tumblr

Social media: tips

• Don't replace letters with emojis
• Don't overuse emojis
• Use CamelCase: use a capital letter at the start of every word within a hashtag
• Don't use special characters in your username

Improving tweet accessibility

Distractions, motion & time limits

Flashing

Don't create content that can cause epileptic seizures.

• Avoid (strobe-like) flashing of 3 or more flashes/second.
• Important: possible trigger for epilepsy, migraines, light sensitivity, sensory overload,...

Photosensitive Epilepsy Analysis Tool (PEAT)

Flashing

Add a warning for users

Examples:

(WARNING: links can trigger seizures)

• Falling.com (flashes of color)
• Pokémon (side-by-side comparison)
• Citroën DS4 (black/white flashes)

Motion

When animation on a webpage starts automatically and plays for longer than 5 seconds:

• Give the user control: add a pause button
• Best practice: avoid autoplay.

Important for people with focus issues and sensory sensitivities.

Motion

• Scrolling text
• Slideshow
• Background video
• Animated GIF
• Flashing content
• SVG animation
• Autoplay
• ...

Examples: -/+

Don't start audio automatically

When an audio fragment starts and plays for more than 3 seconds:

• User must be abke pause or stop the audio manually
• Best practice: don't autoplay audio
• Good example: Amazon Prime

Pop-ups

• Use sparingly
• Avoid unexpected behaviour: content must be related to the intended action
• Never while loading a page

Cookie banners

When a cookie banner overlaps with content:

• Easy to click away
• At the top top of the source code
• Avoid keyboard traps

Time limits

• Notify the user when time limit is about to expire
• Give user the option to extend their session

Responsive
Web
Design

For whom?

• Mobile devices
• People with low vision: usage of text magnification leads to mobile display
• Screenreader user with a non-maximised screen.

Resize text

• Magnification up to 200% without loosing content (e.g. overlap)
• Browser zoom (cmd of ctrl +)
• Is all content still visible within mobile display?

Display orientation

Allow both landscape and portrait mode

Example: a mobile device mounted on a wheelchair cannot be tilted.

Reflow

At a width of 320 CSS pixels:

• No loss of content or functionality
• No horizontal scrolling

320 CSS pixels is equivalent to a starting viewport width of 1280 CSS pixels wide at 400% zoom.

Text spacing

No loss of content or functionality when adjusting style properties:

• Line height (line spacing): at least 1.5 times font size;
• Space between paragraphs: at least 2 times font size;
• Letter spacing (tracking): at least 0.12 times font size;
• Word spacing: at least 0.16 times font size.

Bookmarklet

Don't disable pinch to zoom

<meta content="width=device-width;initial-scale=1.0; 
			maximum-scale=1.0; user-scalable=1;" name="viewport" />

<meta name="viewport" content="user-scalable=no" />

Forms

Label and fields must have visible connection

• Identical value for <label for=""> and <input id=""> (Examples)
• Date format (dd/mm/yyyy or local equivalent)
• Required fields (*)

Fields without visible label

• Use title attribute or aria-label
• Example: slider component in survey

Placeholder is not enough

HTML 5 placeholder attribute does not replace a label

<fieldset>

Legend = label for all fields in the same fieldset

Examples of fieldsets in WAI tutorial

Date picker

• Doesn't have to be accessible
• Give user option to type date as well
• Or use drop-downs for day, month, year

Use standard form fields

• Accessibility already included
• Theoretically possible to create a drop-down or radio buttons using JavaScript, but
• DIY accessibility using ARIA: difficult, often contains mistakes.

Identify input purpose

• Communicate input expectations to browser
• Use autocomplete to enable correct autofill, see example
• Commonly used information like name, address, email, phone number,...
• Provide fields with an autocomplete attribute when a value for it exists: HTML5 specification for Autofill

	<label for="name">Last name</label>
	<input autocomplete="family-name" type="text" id="name" name="name" />
	

	<label for="country">Country</label>
	<input autocomplete="country" type="text" id="country" name="country" />
	

Spam protection

• Don't ask user to retype characters (captcha)
• Use alternative: time analysis, honeypot, email/text verification,...
• Inaccessibility of CAPTCHA: alternatives to visual Turing tests on the web

Form validation

• Every form must include a send button
• Make error messages easy to find (manage focus)
• Describe problem and location of related field
• Combine with visual cues (colour, icons)

Other WCAG success criteria

Meaningful page title

• Title element for each webpage
• Name page | name website

Lang-attribute

• Must be present in HTML-element of each webpage
• Indicates the language of page's content

Examples:

<html lang="nl">
	<html lang="fr">
	<html lang="de">
	<html lang="en">
	

Multiple languages

• Does your page contain multiple languages?
• Provide a lang-attribute for deviating containers.

Example

<div lang="en">
	<a lang="en" href="#">Download the leaflet in English</a>
	<span lang="en">
	

Valid source code

WCAG is a W3C standard and requires correct HTML usage.

http://validator.w3.org/

Down-event

Don't attach the action to the down-event of a key stroke, only to the up-event.

• Prevents 'triggering' an action when unwanted.
• Important for people with a motor impairment.

Multiple ways

More than one way is available to locate a webpage within a set of webpages except where the webpage is the result of, or a step in, a process.

Consistent navigation

Navigational mechanisms that are repeated on multiple webpages within a set of webpages occur in the same relative order each time they are repeated, unless a change is initiated by the user.

Consistent identification

Components that have the same functionality within a set of webpages are identified consistently.

Best practice

You have to register...
	Register
	

Dynamic updates

What?

A user's action triggers a dynamic update within the same page.

Examples

• Extra form fields appear based on one's choice
• Disclosure = button to show/hide content
• New overlay appears
• Results are filtered
• A confirmation or error notification appears
• Search results are shown
• Single page application

Accessibility

• Is the dynamic update predictable for all users?
• How can we announce a dynamic update to a user who doesn't have a visual overview of the screen?

Possible techniques

• Do nothing
• Follow ARIA design patterns
• Move the focus to the info that has appeared
• New info is contained within live region
• Add an explanation

Technique 0: do nothing

• When dynamic update occurs lower in the page, and the user does not have to know that right away.
• E.g. Booking.com: when travelling with children, extra fields appear to provide their age

Technique 1: ARIA design patterns

• Some ARIA design patterns add semantic information that helps to understand dynamic updates.
• Tabs
• Carousel
• Disclosure = show/hide component

Example: disclosure

• = a button that shows or hides contents by expanding or collapsing it
• See article Show and hide content
• Can be done with summary/details
• Disclosure design pattern

aria-expanded

• = an ARIA attribute to be added to the button that expands/collapses
• To indicate its state
• It clarifies the function of the button and indicates that it is a disclosure.
• Aria-expanded="true" means "section is now visible"
• Aria-expanded="false" means "section is now hidden"

Examples

• Language choice SNCB
• Menu in responsive version AnySurfer

Attention

• Correct place
• Indicate correct status at all times
• Neutral label
• Correct hiding technique
• Logic source code order

Correct place

• Add the aria-expanded attribute to the trigger (link or button).
• Don't add it to the container of the content that may be expanded.

Good example

<button class="main-menu-toggle" aria-expanded="false">
	Menu</button>
	

Bad example

Expanded FAQ question:

<a data-toggle="collapse" href="#collapse01">
Question 1</a>
<div id="collapse01" class="panel-collapse" 
aria-expanded="true">

Correct status

• aria-expanded is present with correct value when the page loads.
• Don't add it after the status has changed.
• Adapt status whenever it changes.

Neutral label

• aria-expanded indicates status
• Button label should not indicate an action
• Not OK: show menu or hide search function
• OK: menu or search

Correct hiding technique

• Hide collapsed content with display:none
• Content must also be hidden for screenreaders (avoid techniques like class="sr-only" or "visuallyhidden")

Source code order

• First the button that controls visibility
• Immediately followed by the content that may (not) be visible.

Bad example

• Menu in responsive version of Fine Arts museum
• Expanded content is in source code before the menu link.
• Screenreader and keyboard users won't go back.

Conclusion

The aria-expanded technique can be used if new info appears immediately after the button.

Technique 2: focus management

• When new info appears elsewhere on the page:
• Redirect focus to new info
• Article: learning to focus()

Attention points with focus management

• Move focus to the container of the new content or to the very first element inside.
• You may need to add tabindex="-1" to the element you want the focus to move to.
• Loading new content via AJAX may take some time. Delay the focus movement with one second.

Example: show more

• Search results police website
• After tenth search result follows a button "load more".
• Focus moves from "load more" button to beginning of new content.

Conclusion

• Focus management is technique to be used when the user must interact with new content.
• Sometimes new info appears that one just needs to read.

Technique 3: live region

• = a section where content may be updated
• Example: title of currently playing video on Youtube
• When next video starts, info in this section is updated.

Result

• Screenreader automatically speaks modified content upon change
• Read only; focus does not move
• User can't ask to repeat it
• User has no control over live region

Voorbeeld: wachtwoordsterkte

Voorbeeld: waarschuwing

Technically

• role="status" or aria-live="polite"
• role="alert" or aria-live="assertive"
• Polite waits until screenreader is finished talking; Assertive interrupts
• aria-live="off": section is (temporarily) not a live region.

Attention

• Container where new info appears or changes, must already be marked as live region prior to the update.
• E.g. if you want to be able to add an error message to a form field, a container with aria-live="polite" must be present when the page loads. Later, you will inject the error message into that container.

Possible use cases

• The results counter for a dynamic filter
• The total price when items change in the shopping cart
• Password strength that changes from weak to medium to strong
• A chat box

Don't use live regions

• When information changes frequently: e.g. time remaining counter for a video that is updated every second
• For information that is not important: e.g. Never use for a slide show
• When there are many automatic updates on a page: e.g. real time stocks

Conclusion

• Live region can be a useful technique to attract user's attention to info that is added/changed/modified.
• Only when user does not need to interact with that information.

Technique 4: add explanation

If no authoring practice exists for the widget you're building:

• Try to use previous techniques where apropriate
• Sometimes you may want to add (invisible) explanation
• Extra headings may be helpful to facilitate navigation between sections

Example: dynamic search function

Invisible text before search field:

As soon as you have entered 5 characters in the search box, search results will appear under the heading "Publications found".

Example: dynamic filter

Provide an "invisible" heading at the top of filter options and one at the top of the results section.

Monitoring multiple dynamic updates on a screen, remains a challenge for users who have no overview over the screen (e.g. a webinar).

Video & audio

• Audio only: text transcript
• Video only: text transcript or audio description
• Video with both audio and video:
  • Captions
  • If necessary: audio description
  • Useful but not mandatory: text transcript and sign language
• Accessible video player

Text transcripts must contain

• All spoken lines
• Name of speaker
• Other important sounds
• Audible emotions

Great examples

• Freakonomics: podcasts with text transcript
• Bridging the gap between the deaf and hearing community (transcript on YouTube)
• Easy DIY projects for kid engineers (transcript under video)

Subtitles for deaf people (captions)

• In language spoken in the video
• Spoken text as literal as possible
• Must contain audible but invisible sounds:
  • Who is talking?
  • Important sounds
  • Silence
  • Tone of voice, audible but invisible emotions

Automated synchronisation

Automated captions YouTube

• Can be a useful starting point for a textual transcript
• Inadequate quality:
  • Wrong words
  • No punctuation
  • Moves like live news feed

Altering YouTube subtitles

• Download automated subtitles
• Remove all time stamps
• Correct all mistakes
• Use punctuations, capital letters, and full sentences
• Add all missing information

Altering YouTube subtitles

• Upload new file back to YouTube
• YouTube will do the synchronising
• Adjust time stamps if necessary
• Deactivate automated captions

Saves time

• AI writes most spoken text correctly
• Helps when synchronisation
• Text transcript and captions are 95% identical

Example:

• Live captioning: Making digital media more accessible with a single tap

Captions on social media

• YouTube (tutorial)
• Facebook
• Twitter
• TikTok (auto captions)
• LinkedIn

Audio description

• Extra audio track for blind users
• Describes non-audible cues
• Not necessary for talking head videos
• The Interviewer
• Netflix > Browse > audio & subtitles
• #WeThe15 with audiodescription (extended)

Avoid missing audible cues

Call us on this number.

• Make the TV host say the actual phone number
• Or, include the number in text separate of the video

This graph shows the evolution of the number of patients admitted to hospital last week.

The number of patients that were admitted to hospital went down from 100 on Monday to 50 on Sunday.

Expertise needed

• Adding audio description to existing videos is a specialist job
• Limited silence in which descriptions can fit
• Discerning crucial information is essential
• Quality recording with a clear voice

New video or audio

• Save the script
• Closed captions are better than open captions
• Avoid the necessity of audio description
• Use AI to transcribe spoken words into text

Accessible video player

• Is it keyboard accessible?
• Are buttons correctly labeled?
• When controls are no longer visble, can they be called back?

Apps

Settings accessibility

• Android and iOS
• Lots of settings to personalise your device with
• Options to connect device to assistive tech like a braille display

Accessible apps

• Most WCAG criteria also apply to mobile devices
• Solutions are different in every programming environment

Pointers

Provide an alternative gesture based on single clicks for complex gestures, such as:

• Pinch to zoom
• Follow a trajectory
• Tabbing with 2 or 3 fingers

Motion detection

• Don't use motion detection as sole trigger for action
• Provide alternatives
• Allow user to deactivate motion detection

Android

• Build more accessible apps | Android Developers
• Google App for developers to test the accessibility of apps

iOS

• Accessibility Programming Guide for iOS: Making Your iOS App Accessible
• Learn to create accessible iOS apps with the Deque university app

Widgets

• Which widget?
• Can it be built with native HTML?
• Is a design pattern available?
• Has it been applied correctly?
• Does the widget work for keyboard users?
• Are dynamic updates predictable?

Hamburger or other icons?

Questions

• Are these icons accessible and operable with a keyboard?
• Relevant link text?
• If collapsable element: add aria-expanded to indicate state
• Correct reading and tab order?

Cards

Questions

• Semantics: list or headings?
• Relevant link text?
• Logical sequence order?
• Do images need alt texts or are they decorative?

Examples

• Office for National Statistics UK
• BBC
• VRT News

Conclusion

• Context dependent
• Article: Inclusive design component for cards

Overlay

• Shown on top of current web page
• User is not supposed to interact with the underlying page
• Build them as a modal dialog

Modal dialog

• ARIA design pattern
• Example

Focus management

• When opened: redirect focus to new info
• Focus limited to overlay only (keyboard trap)
• After closing: focus on original starting point

ARIA

• role="dialog" because dialog element doesn't have general support yet
• aria-modal="true" to make content outside modal dialog inaccessible
• also possible with aria-hidden="true", but more work and higher risk

Close button

• Label with clear meaning
• Logical reading and tab order
• Focus outline must be visible
• Close with ESC

Documents

Documents

• Use webpages when possible
• Use documents only when necessary
• Create accessible templates to use within organisation

Accessible documents

• Basic principles are the same for webpages
• How to: depends on software used
• Accessible Digital Office Document (ADOD) Project

Word documents

• Use heading styles
• Use built-in functionalities, e.g. use "track changes" instead of crossing out text,...
• Create accessible Word documents

PDF documents

• Start by making the original documents accessible
• Tagged PDF when export from Word and InDesign

Create and verify PDF accessibility (Acrobat Pro)

Forms

• Not in Word!
• Possible to create PDF to fill in
• Web forms are best option for users, developers, and data processing

Some allround advice

Use accessible basics

Do certain components reoccur in each of your projects? Avoid double work: make them accessible.

Accessible components

• Gov.uk design system
• Heydon's Inclusive Components
• WAI-ARIA Authoring Practices

Make it easy for editors

Test while you work

Having to correct accessibility at the end of your project will cost you extra effort and time (=money), and will lead to frustrations.