Web Accessibility Standards, Requirements, & Legislation (including WCAG)

The standards for web accessibility are complex, it’s true. This resource discusses the rules in Canada, and breaks down exactly what is needed to meet the all-important Web Content Accessibility Guidelines (WCAG). Even when simplified, though, WCAG can be complex — so this may be one document you keep coming back to!

  • Subject(s):

    Website Accessibility

  • Resource Type(s):

    Standards and Best Practices

  • Audience:

    Technical

Suggested Prerequisite

Before reading this, you might want to read:

Introduction

When built (or remediated) with accessibility in mind, websites can present digital content that can be easily accessed and used by almost any potential site visitor. To help people make the most accessible websites possible, the Web Accessibility Initiative (WAI) has created The Web Content Accessibility Guidelines (WCAG)—guidelines which provide detailed recommendations on how to make all kinds of digital content accessible, and set the standard for web accessibility. And, to encourage (or mandate…) compliance, the Government of Canada and some provinces have released legislation around web accessibility.

Legislation

In Canada, there is some legislation which mandates requirements for accessibility – but in general, these requirements boil down to meeting WCAG. For example, the Accessible Canada Act (ACA, 2019) is expected to adopt the latest standard of WCAG at Level AA conformance for all websites and web applications (don’t worry – if you are not sure what this means, it is explained below!).

The Accessibility for Ontarians with Disabilities Act (AODA, 2005) is more explicit – as outlined in the Information and Communications Standards (see sections 9 – 19) part of Ontario Regulation 191/11 under the AODA, public websites and web content posted after January 1, 2012, must meet the WCAG 2.0 Level AA success criteria, except for the guidelines around live captions and pre-recorded audio descriptions.

Whether or not accessibility is mandated for your organization, it is of course fantastic to ensure that your website and digital content can be easily accessed by any potential visitor. On this page, we’ll break down some of the Web Content Accessibility Guidelines so you can dive in to improving your site!

Web Content Accessibility Guidelines (WCAG)

The Web Content Accessibility Guidelines we will discuss here are from version 2.1 (released in 2018). Note that an updated version—2.2—is expected in the Fall 2022, so stay tuned! Don’t worry though, implementing what we share below will only serve to set you up for success, even when the new version of the guidelines comes into force.

Basics of WCAG

The Web Content Accessibility Guidelines are organized under four principles. Content must be:

  • Perceivable – Information and user interface components must be presentable to users in ways they can perceive (e.g. Seeing text, hearing text read out by a screen reader, or feelingbraille text).
  • Operable – User interface components and navigation must be operable (e.g. it should be navigable by “mousing” as well as by using keyboard navigation)
  • Understandable – Information and the operation of a user interface must be understandable. This applies to things like the language of the site, and the consistency of navigation. Everything needs to be easily understood.
  • Robust – Content must be robust enough that it can be interpreted reliably by a wide variety of assistive technologies (e.g. Screen Readers and Magnifiers). Basically, code should be well-formed, operations should be defined, and an effort should be made to build sites that are compatible with assistive technologies.

And, there are three success criteria levels

  • WCAG A - Minimum level – without addressing these items, barriers exist that cannot be overcome by assistive technology.  This level affects the broadest group with the most benefits, and is absolutely essential. Some barriers will still exist which impact certain groups of users. 
  • WCAG AA - More accessible – Level AA establishes a level of accessibility which should work with most assistive technology on desktop and mobile devices.
  • WCAG AAA – Even more accessible– Some AAA accessibility criteria cannot be applied everywhere, so level AAA is generally not required.

Each principle has a set of criteria under each success criteria level. Here, we will give a broad overview of each criterion, but for in-depth explanations and examples for the criterion, check out some of the “Links to More Information”.

WCAG Criteria: General Guidelines

Note that this overview will only include the A and AA criteria. For AAA, see the WCAG documentation; meeting AAA would be awesome, but it is not technically required by any standards, so we have left it off of this resource. In this table, we have the Principle (Perceivable, Operable, Understandable, and Robust), the category, the specific criterion/guideline, the level (A or AA), and how to meet it. We have provided simplified language (which should help people who are less experienced with web development) and also the language provided by WCAG’s creators. 

Important Note! Some of the “Simplified Language” don’t address some of the more complex implementations that are possible in web development. Be sure to dig into the links for more in-depth information. 

Principle: 1. Perceivable

Category: 1.1 Text Alternatives

Criterion: 1.1.1 Non-text Content

Level: A

Simplified Language: Include alternative text for all non-decorative images.

From WCAG: All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below.

  • Controls, Input: If non-text content is a control or accepts user input, then it has a name that describes its purpose. (Refer to Success Criterion 4.1.2 for additional requirements for controls and content that accepts user input.)
  • Time-Based Media: If non-text content is time-based media, then text alternatives at least provide descriptive identification of the non-text content. (Refer to Guideline 1.2 for additional requirements for media.)
  • Test: If non-text content is a test or exercise that would be invalid if presented in text, then text alternatives at least provide descriptive identification of the non-text content.
  • Sensory: If non-text content is primarily intended to create a specific sensory experience, then text alternatives at least provide descriptive identification of the non-text content.
  • CAPTCHA: If the purpose of non-text content is to confirm that content is being accessed by a person rather than a computer, then text alternatives that identify and describe the purpose of the non-text content are provided, and alternative forms of CAPTCHA using output modes for different types of sensory perception are provided to accommodate different disabilities.
  • Decoration, Formatting, Invisible: If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.

Category: 1.2 Time-based Media

Criterion: 1.2.1 Audio-only and Video-only (Prerecorded)

Level: A

Simplified Language: Include alternate ways of presenting the information, like transcripts for podcasts, or text descriptions for a silent video. 

From WCAG: For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such:

  • Prerecorded Audio-only: An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.
  • Prerecorded Video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.

Category: 1.2 Time-based Media

Criterion: 1.2.2 Captions (Prerecorded)

Level: A

Simplified Language: Include captions in pre-recorded videos.

From WCAG: Captions are provided for all pre-recorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

Category: 1.2 Time-based Media

Criterion: 1.2.3 Audio Description or Media Alternative (Prerecorded)

Level: A

Simplified Language: Include audio descriptions or media alternatives for pre-recorded video content.

From WCAG: An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

Category: 1.2 Time-based Media

Criterion: 1.2.4 Captions (Live)

Level: AA

Simplified Language: Include captions for live video.

From WCAG: Captions are provided for all live audio content in synchronized media.

Category: 1.2 Time-based Media

Criterion: 1.2.5 Audio Description (Prerecorded)

Level: AA

Simplified Language: Include audio descriptions for pre-recorded video content (unlike 1.2.3, audio description is required to meet this; alternate approaches like a text description only meets 1.2.3, Level A).

From WCAG: Audio description is provided for all prerecorded video content in synchronized media.

Category: 1.3 Adaptable

Criterion: 1.3.1 Info and Relationships

Level: A

Simplified Language: Ensure that the information on a page is structured and well organized, and uses HTML correctly. HTML should be used wherever possible, for headings, lists, tables, asides, blockquotes, emphasized text, etc.

From WCAG: Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.

Category: 1.3 Adaptable

Criterion: 1.3.2 Meaningful Sequence

Level: A

Simplified Language: Present the information in a logical reading order, ensuring that the order in the code matches the visual reading order

From WCAG: When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.

Category: 1.3 Adaptable

Criterion: 1.3.3 Sensory Characteristics

Level: A

Simplified Language: Ensure that instructions provided for understanding and interacting with or operating content don’t only rely on “sensory characteristics” such as shape, colour, size, visual location, orientation, or sound.

From WCAG: Instructions provided for understanding and operating content do not rely solely on sensory characteristics of components such as shape, colour, size, visual location, orientation, or sound.

Category: 1.3 Adaptable

Criterion: 1.3.4 Orientation

Level: AA

Simplified Language: Ensure that the site’s content does not restrict its view and operation to a one screen orientation ( portrait or landscape), unless a specific display orientation is absolutely required.

From WCAG: Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is essential.

Category: 1.3 Adaptable

Criterion: 1.3.5 Identify Input Purpose

Level: AA

Simplified Language: Ensure that the purpose of form fields (like name, email address, password) can be understood by the user’s software/computer. Basically, use correct mark-up for forms, and consider using the HTML autocomplete attribute. 

From WCAG: The purpose of each input field collecting information about the user can be programmatically determined when:

  • The input field serves a purpose identified in the Input Purposes for User Interface Components section; and
  • The content is implemented using technologies with support for identifying the expected meaning for form input data.

Category: 1.4 Distinguishable

Criterion: 1.4.1 Use of Color

Level: A

Simplified Language: Ensure that colour is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

From WCAG: Colour is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.

Category: 1.4 Distinguishable

Criterion: 1.4.2 Audio Control

Level: A

Simplified Language: Ensure that users are able to pause, stop, mute or control the volume of any audio that plays for more than 3 seconds.

From WCAG: If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.

Category: 1.4 Distinguishable

Criterion: 1.4.3 Contrast (Minimum)

Level: AA

Simplified Language: Ensure that the contrast between text and its background is sufficient (4.5:1 for 18pt size and lower, 3:1 for larger size text). 

From WCAG: The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following:

  • Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
  • Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
  • Logotypes: Text that is part of a logo or brand name has no contrast requirement.

Category: 1.4 Distinguishable

Criterion: 1.4.4 Resize text

Level: AA

Simplified Language: Ensure that text can be resized up to 200% larger than the original, without causing any issues with content or function.

From WCAG: Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality.

Category: 1.4 Distinguishable

Criterion: 1.4.5 Images of Text

Level: AA

Simplified Language: Avoid using images of text unless they are absolutely necessary – use HTML instead.

From WCAG: If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following:

  • Customizable: The image of text can be visually customized to the user’s requirements;
  • Essential: A particular presentation of text is essential to the information being conveyed.

Category: 1.4 Distinguishable

Criterion: 1.4.10 Reflow

Level: AA

Simplified Language: Users should be able to magnify web pages by up to 400% without losing functionality – this means ensuring that content is reflowable and responsive as users zoom in. 

From WCAG: Content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions for:

  • Vertical scrolling content at a width equivalent to 320 CSS pixels;
  • Horizontal scrolling content at a height equivalent to 256 CSS pixels;
  • Except for parts of the content which require a two-dimensional layout for usage or meaning.

Category: 1.4 Distinguishable

Criterion: 1.4.11 Non-text Contrast

Level: AA

Simplified Language: Ensure that the contrast between non-text content (like buttons, radio button indicators, graphics, etc.) and background is sufficient – at least 3:1.

From WCAG: The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent colour(s):

  • User Interface Components: Visual information required to identify user interface components and states, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author;
  • Graphical Objects: Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.

Category: 1.4 Distinguishable

Criterion: 1.4.12 Text Spacing

Level: AA

Simplified Language: When users are able to manipulate text-spacing, ensure that no loss of meaning, content, or function occurs based on line/letter/word spacing.

From WCAG: In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:

  • Line height (line spacing) to at least 1.5 times the font size;
  • Spacing following paragraphs to at least 2 times the font size;
  • Letter spacing (tracking) to at least 0.12 times the font size;
  • Word spacing to at least 0.16 times the font size.

Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.

Category: 1.4 Distinguishable

Criterion: 1.4.13 Content on Hover or Focus

Level: AA

Simplified Language: When “hover text” appears (either by hovering over the trigger text with a mouse pointer, or by navigating to the word using keyboard navigation – called “focus”), this text must be:

  • Dismissible: without moving the pointer or focus, the user must be able to dismiss the hover text, i.e. by hitting Escape;-hoverable: meaning that the user can move the pointer around the hover text (Wikipedia pages do this well); and
  • persistent: the hover text must remain until the user dismisses it, or moves the pointer or focus away (i.e., it should not only last for a few seconds and disappear on its own).

From WCAG: Where receiving and then removing pointer hover or keyboard focus triggers additional content to become visible and then hidden, the following are true:

  • Dismissible: A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;
  • Hoverable: If pointer hover can trigger the additional content, then the pointer can be moved over the additional content without the additional content disappearing;
  • Persistent: The additional content remains visible until the hover or focus trigger is removed, the user dismisses it, or its information is no longer valid.

Exception: The visual presentation of the additional content is controlled by the user agent and is not modified by the author.


Principle: 2. Operable

Category: 2.1 Keyboard Accessible

Criterion: 2.1.1 Keyboard

Level: A

Simplified Language: Ensure that users are able to operate all of the functions on a site using a keyboard interface.

From WCAG: All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user’s movement and not just the endpoints.

Category: 2.1 Keyboard Accessible

Criterion: 2.1.2 No Keyboard Trap

Level: A

Simplified Language: Users should be able to move keyboard focus away from a component of a site or page (like a calendar widget or modal dialog box) using the standard keyboard interface – if this is not possible, users should be advised on how to move focus away.

From WCAG: If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away.

Category: 2.1 Keyboard Accessible

Criterion: 2.1.4 Character Key Shortcuts

Level: A

Simplified Language: When a site has keyboard shortcuts that use only a textual character, ensure that the user has the option of one or more of the following: disabling them, remapping/reassigning them, or ensuring that the unique shortcuts are only active when the component that uses them is being interacted with.

From WCAG: If a keyboard shortcut is implemented in content using only letter (including upper- and lower-case letters), punctuation, number, or symbol characters, then at least one of the following is true:

  • Turn off: A mechanism is available to turn the shortcut off;
  • Remap: A mechanism is available to remap the shortcut to include one or more non-printable keyboard keys (e.g., Ctrl, Alt);
  • Active only on focus: The keyboard shortcut for a user interface component is only active when that component has focus.

Category: 2.2 Enough Time

Criterion: 2.2.1 Timing Adjustable

Level: AA

Simplified Language: If content on a site (like log-in periods, amount of time given to complete a purchase, etc.) has a time limit, then at least one of the following options is available:

  • the user can turn off the time limit;user can adjust the time limit; or
  • user is warned before the time limit expires, and is given at least 20 seconds to extend the time limit with a simple action.

There are exceptions for real-time restrictions (like an auction), if the time limit is essential, or if the time limit is more than 20 hours.

From WCAG: For each time limit that is set by the content, at least one of the following is true:

  • Turn off: The user is allowed to turn off the time limit before encountering it; or
  • Adjust: The user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or
  • Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, “press the spacebar”), and the user is allowed to extend the time limit at least ten times; or
  • Real-time Exception: The time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or
  • Essential Exception: The time limit is essential and extending it would invalidate the activity; or
  • 20 Hour Exception: The time limit is longer than 20 hours.

Category: 2.2 Enough Time

Criterion: 2.2.2 Pause, Stop, Hide

Level: AA

Simplified Language: For content that moves, blinks, scrolls, or auto-updates, the following is true:

  • For any moving, blinking or scrolling information that (1) starts automatically, (2) lasts more than five seconds, and (3) is presented in parallel with other content, there is an option for the user to pause, stop, or hide it (unless the effect is essential); and
  • For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is an option for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.

From WCAG: For moving, blinking, scrolling, or auto-updating information, all of the following are true:

  • Moving, blinking, scrolling: For any moving, blinking or scrolling information that (1) starts automatically, (2) lasts more than five seconds, and (3) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it unless the movement, blinking, or scrolling is part of an activity where it is essential; and
  • Auto-updating: For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.

Category: 2.3 Seizures and Physical Reactions

Criterion: 2.3.1 Three Flashes or Below Threshold

Level: A

Simplified Language: Ensure that the site does not contain anything that flashes more than three times in any one second period (unless that flashing content is sufficiently small and the flashes are of low contrast and do not contain too much red).

From WCAG: Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.

Category: 2.4 Navigable

Criterion: 2.4.1 Bypass Blocks

Level: A

Simplified Language: Ensure that users are able to bypass blocks of content that are repeated on multiple Web pages, like adding a link at the top of each page that goes directly to the main content area.

From WCAG: A mechanism is available to bypass blocks of content that are repeated on multiple Web pages.

Category: 2.4 Navigable

Criterion: 2.4.2 Page Titled

Level: A

Simplified Language: Include descriptive <title> information for each web page.

From WCAG: Web pages have titles that describe the topic or purpose.

Category: 2.4 Navigable

Criterion: 2.4.3 Focus Order

Level: A

Simplified Language: If the order of information/actions on a page should be navigated in a certain order that affects meaning, ensure that keyboard navigation follows the correct sequence.

From WCAG: If a Web page can be navigated sequentially and the navigation sequences affect meaning or operation, focusable components receive focus in an order that preserves meaning and operability.

Category: 2.4 Navigable

Criterion: 2.4.4 Link Purpose (In Context)

Level: A

Simplified Language: Ensure that every active link has useful link text, like “View our Spring Catalogue” instead of “Click Here”.

From WCAG: The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general.

Category: 2.4 Navigable

Criterion: 2.4.5 Multiple Ways

Level: AA

Simplified Language: Ensure that there is more than one way to locate a particular page on a site, like having menu navigation, links between pages, a search function, etc.

From WCAG: More than one way is available to locate a Web page within a set of Web pages except where the Web Page is the result of, or a step in, a process.

Category: 2.4 Navigable

Criterion: 2.4.6 Headings and Labels

Level: AA

Simplified Language: Ensure that headings and labels are descriptive and useful, and accurately describe the section they head, the paragraph they introduce, or the function of the form field they are labeling. 

From WCAG: Headings and labels describe topic or purpose.

Category: 2.4 Navigable

Criterion: 2.4.7 Focus Visible

Level: AA

Simplified Language: Ensure that any component of a page that can be used by a keyboard, like a search field, gives a visual indication when it is active (like a blinking cursor, or highlighted text).

From WCAG: Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible.

Category: 2.5 Input Modalities

Criterion: 2.5.1 Pointer Gestures

Level: A

Simplified Language: Ensure that any site function that is designed to be accomplished by using either “multi-point” or “path-based” gestures (like zooming into a map by pinching and zooming with two fingers on a touch-screen, or drawing a pattern to unlock a phone) can be achieved by using a single pointer or having non-path based approach ((like clicking plus or minus to zoom, or giving users the option of using a passcode instead of a pattern). 

From WCAG: All functionality that uses multipoint or path-based gestures for operation can be operated with a single pointer without a path-based gesture, unless a multipoint or path-based gesture is essential.

Category: 2.5 Input Modalities

Criterion: 2.5.2 Pointer Cancellation

Level: A

Simplified Language: Ensure that one of the following is true for any site function that is activated with a “single-pointer” input (i.e., a single tap or a click, double-taps and clicks, long presses, and path-based gestures):

  • “No down-event”: The down-event (e.g., when the user clicks but has not yet released, or taps but has not lifted their finger) does not execute the function
  • “Abort or Undo”:The function is completed on the up-event (e.g., when the user releases the click or lifts their finger), and a mechanism is available to abort the function before completion (like moving the pointer away before releasing) or to undo the function after completion (like an option to “Cancel” if a dialog is opened);
  • “Up Reversal”: If the down-event triggers an action or behaviour (like causing a pop-up to appear, or playing a video), the up-event reverses any outcome of the preceding down-event (i.e., the pop-up disappears, or the video stops playing;
  • “Essential”: Sometimes, completing the function on the down-event is essential — a common example is when there is a keyboard emulator – having the “down-event” of the keystroke trigger the appearance of the letter is normal behaviour — this is OK!

From WCAG: For functionality that can be operated using a single pointer, at least one of the following is true:

  • No Down-Event: The down-event of the pointer is not used to execute any part of the function;
  • Abort or Undo: Completion of the function is on the up-event, and a mechanism is available to abort the function before completion or to undo the function after completion;
  • Up Reversal: The up-event reverses any outcome of the preceding down-event;
  • Essential: Completing the function on the down-event is essential.

Category: 2.5 Input Modalities

Criterion: 2.5.3 Label in Name

Level: A

Simplified Language: For user interface components with labels (like buttons) that include text or images of text, the “programmatic” name (the one that can be read by the computer) should contain the text that is presented visually. This ensures that there is no confusion when a screen reader user focuses on that component. 

From WCAG: For user interface components with labels that include text or images of text, the name contains the text that is presented visually.

Category: 2.5 Input Modalities

Criterion: 2.5.4 Motion Actuation

Level: A

Simplified Language: Ensure that any function that is activated by motion (like shaking a device to undo an action or an input) can also be accomplished by an interface component (like a button to “Cancel” or “Undo”). 

From WCAG: Functionality that can be operated by device motion or user motion can also be operated by user interface components and responding to the motion can be disabled to prevent accidental actuation, except when:

  • Supported Interface: The motion is used to operate functionality through an accessibility supported interface;
  • Essential: The motion is essential for the function and doing so would invalidate the activity.

Principle: 3. Understandable

Category: 3.1 Readable

Criterion: 3.1.1 Language of Page

Level: A

Simplified Language: Define the language of the page in the HTML element, for each page.

From WCAG: The default human language of each Web page can be programmatically determined.

Category: 3.1 Readable

Criterion: 3.1.2 Language of Parts

Level: AA

Simplified Language: Define the language of phrases/text in other languages (when it is different from the main language of the page). There are exceptions, like names (e.g., Marcel Proust), technical terms (e.g., zeitgeist), or words/phrases that are common in English (or the main language of the site) (e.g., schadenfreude, rendezvous, etc.).

From WCAG: The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text.

Category: 3.2 Predictable

Criterion: 3.2.1 On Focus

Level: A

Simplified Language: Ensure that users can explore the content of a page without triggering an unexpected change of context. For example, clicking into a form field should not open a pop-up; pressing the down arrow in a drop-down menu should not open a new window or page. 

From WCAG: When any user interface component receives focus, it does not initiate a change of context.

Category: 3.2 Predictable

Criterion: 3.2.2 On Input

Level: A

Simplified Language: Ensure that users can change the “setting” of an interface component (e.g., check a checkbox, enter text into a field, etc.) without triggering a change of context (e.g., opening a new window or page, rearranging the content of the page, etc.).

From WCAG: Changing the setting of any user interface component does not automatically cause a change of context unless the user has been advised of the behavior before using the component.

Category: 3.2 Predictable

Criterion: 3.2.3 Consistent Navigation

Level: AA

Simplified Language: Navigational mechanisms (e.g., navigation menus, search fields, “skip to navigation” links, etc.) need to occur in the same relative order on multiple Web pages within a set of Web pages. This ensures that the user can easily navigate web pages, since there is predictability.

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

Category: 3.2 Predictable

Criterion: 3.2.4 Consistent Identification

Level: AA

Simplified Language: Ensure that components with the same functionality (e.g., a button that “skips to the next page”, or an icon of an envelope that users can click to send a message to a person, etc.) are identified consistently (e.g., the text always says “skip to next page” instead of sometimes saying “skip to next page” and other times saying the name of the next page instead; or the envelope icon sometimes opens up a message form, and sometimes opens up the users’ mail platform). 

From WCAG: Components that have the same functionality within a set of Web pages are identified consistently.

Category: 3.3 Input Assistance

Criterion: 3.3.1 Error Identification

Level: A

Simplified Language: Ensure that when input errors ( which are most commonly errors or missing information in forms) are automatically detected, the item that is in error is identified and the error is described to the user in text (e.g., if they skip a field, or add incorrect information to a required field, text like “Email address required” or “Postal code does not exist” should appear by the field when the form reloads). Additional visual cues can appear as well, like red text or highlighting, but ensure that there is a textual indicator.

From WCAG: If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text.

Category: 3.3 Input Assistance

Criterion: 3.3.2 Labels or Instructions

Level: A

Simplified Language: Provide clear labels and/or instructions to users to help ensure that they are able to easily and correctly fill out forms (e.g., the needed date format is included for a field asking for a date, or required vs. optional fields are clearly labeled, etc.).

From WCAG: Labels or instructions are provided when content requires user input.

Category: 3.3 Input Assistance

Criterion: 3.3.3 Error Suggestion

Level: AA

Simplified Language: Ensure that users receive appropriate suggestions for correction of an input error if it is possible. If an input error is automatically detected and suggestions for correction are known (e.g., If the error is in the format of the input, the suggestion shows the correct format, like ‘The date must be in the form DD/MM/YYYY’). 

From WCAG: If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content.

Category: 3.3 Input Assistance

Criterion: 3.3.4 Error Prevention (Legal, Financial, Data)

Level: AA

Simplified Language: For web pages that cause legal commitments or financial transactions for the user, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following must be true:

  • Reversible: Submissions are reversible.
  • Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
  • Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

From WCAG: For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following is true:

  • Reversible: Submissions are reversible.
  • Checked: Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
  • Confirmed: A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

Principle: 4. Robust

Category: 4.1 Compatible

Criterion: 4.1.1 Parsing

Level: A

Simplified Language: Ensure that all elements have complete start and end tags (like <p>…</p>, for a very basic example). Any missing parts will mean that technology, like screen readers, will run into issues when reading the site’s content.

From WCAG: In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features.

Category: 4.1 Compatible

Criterion: 4.1.2 Name, Role, Value

Level: A

Simplified Language: The name and role of all user interface components (like link, form elements, etc.) need to be able to be “programmatically determined” (i.e., understood by software). Important note: This success criterion is primarily for Web authors who develop or script their own user interface components. Standard HTML controls already meet this success criterion when used according to specification.

From WCAG: For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies.

Category: 4.1 Compatible

Criterion: 4.1.3 Status Messages

Level:

Simplified Language: Sometimes, when a user completes an action (like running a search, submitting a form, or skipping a form field), a status message (like “5 results returned”, “registration form submitted”, or “email address required”) will appear on the page. Ensure that this content is designed to be announced by a screen reader, as it often does not happen automatically. To ensure that status messages are read, use an ARIA role like one of the following (but note that there are more available):

  • role=”alert”
  • role=”status”
  • role=”log”

Note: Be sure to use the correct role. The “alert” role causes a screen reader to interrupt what it’s currently speaking and announce the alert; it would be appropriate for the example situation of “email address required”. Something like “5 results returned” is less urgent and could use a role such as “status”. This will still be announced but will not cause an interruption.

From WCAG: In content implemented using markup languages, status messages can be programmatically determined through role or properties such that they can be presented to the user by assistive technologies without receiving focus.

Accessibility Overlays

You may have heard of “Accessibility Overlays”—products depicted as an “automated solution” that modify the code of a web page, often using JavaScript. These products are usually in the form of a plugin, app, toolbar, or widget, and the companies that create and promote the use of accessibility overlays claim their products automatically detect and fix web accessibility issues. Accessibility overlays always leave out both technical points of web site accessibility, as well as the users themselves, thus resulting in exclusionary processes and products. Moreover, accessibility overlays and automation of remediation are far from perfect: these tools often fail to correctly identify problems in several areas including keyboard traps that prevent users from using form fields, missing links, focus order, quality and relevance of image description and alt-text, use of layout tables, closed captions, inaccessible captchas, and misidentified language.

All this to say: Accessibility Overlays are not at all a recommended approach to accessibility. 

Next Steps

1

Checking the Accessibility of a Website

Reviewing Website Accessibility

This resource gives a brief overview of the existing options for reviewing the accessibility of a website, including using checklists, running automated checking tools, and hiring people to audit a site.

Subject(s): Website Accessibility
Resource Type(s): Standards and Best Practices
Audience:
Technical
2

Web Accessibility Audit Checklists

Checklists for Website Accessibility

This resource offers two checklists for web accessibility one: a simplified one, which will help ensure that a site has paid close attention to accessibility standards, and a more advanced one based on the WCAG…

Subject(s): Website Accessibility
Resource Type(s): Checklist
Audience:
Technical

External Links to More Information

Web Content Accessibility Guidelines

The Web Content Accessibility Guidelines (WCAG) from the World Wide Web Consortium (W3C) are a set of guidelines designed to make web content accessible to people with disabilities. They are organized under four principles: perceivable, operable, understandable, and robust. There are three conformance levels: A, AA, and AAA. AA is recommended. The guidelines cover the content itself, such as text and images, and also the markup used to structure it.

WCAG 2.1 At a Glance

This “At a Glance” page provides a paraphrased summary of Web Content Accessibility Guidelines (WCAG) 2.1. It is non-technical, highly human-readable, and a great place to start learning about the Web Content Accessibility Guidelines.

WAVE Web Accessibility Evaluation Tool

An accessibility checking tool that checks for possible accessibility issues on a web page. Issues that are automatically found are indicated, and it also provides information to help with manual checking. It is a great place to start testing a website, but does require some technical knowledge of WCAG.

5 Website Accessibility Checkers You Need Today

This blog post recommends five automated tools that can be used to check web accessibility. It mentions that manual testing is also needed in addition to automated checks. Tools discussed are WAVE: Website Accessibility Evaluation tool, SortSite, aXe: the Accessibility Engine, Pa11y, and Tota11y.

Overlay Fact Sheet

The Overlay Fact Sheet is an open statement providing a high level overview of what overlays are and what they can and cannot do. It provides clear facts in an easy to digest format, and provides actual opinions of people with disabilities regarding their experiences with overlays.

Content Source Acknowledgement

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