Guidelines

WCAG 2.1 Guidelines

The following checklist is based on WebAIM’s WCAG 2.1 Checklist . It is intended for training purposes and includes only the Level A and AA success criteria.

True WCAG compliance must be evaluated using the official WCAG 2.1 guidelines .

Perceivable

Web content is made available to the senses – sight, hearing, and/or touch

Guideline 1.1

Text Alternatives: Provide text alternatives for any non-text content

Success Criteria WebAIM’s Recommendations
1.1.1 Non-text Content
(Level A)
  • All images, form image buttons, and image map hot spots have appropriate, equivalent alternative text .
  • Images that do not convey content, are decorative, or contain content that is already conveyed in text are given null alt text (alt=””) or implemented as CSS backgrounds. All linked images have descriptive alternative text.
  • Equivalent alternatives to complex images are provided in context or on a separate (linked and/or referenced via longdesc) page.
  • Form buttons have a descriptive value.
  • Form inputs have associated text labels or, if labels cannot be used, a descriptive title attribute.
  • Embedded multimedia is identified via accessible text.
  • Frames are appropriately titled .

Guideline 1.2

Time-based Media: Provide alternatives for time-based media

NOTE: If the audio or video is designated as an alternative to web content (e.g., an audio or sign language version of a web page, for example), then the web content itself serves as the alternative.

Success Criteria WebAIM’s Recommendations
1.2.1 Prerecorded Audio-only and Video-only
(Level A)
  • A descriptive text transcript (including all relevant visual and auditory clues and indicators) is provided for non-live, web-based audio (audio podcasts, MP3 files, etc.).
  • A text or audio description is provided for non-live, web-based video-only (e.g., video that has no audio track).
1.2.2 Captions (Prerecorded)
(Level A)
  • Synchronized captions are provided for non-live, web-based video (YouTube videos, etc.)
1.2.3 Audio Description or Media Alternative (Prerecorded)
(Level A)
1.2.4 Captions (Live)
(Level AA)
  • Synchronized captions are provided for all live multimedia that contains audio (audio-only broadcasts, web casts, video conferences, Flash animations, etc.)
1.2.5 Audio Description (Prerecorded)
(Level AA)
  • Audio descriptions are provided for all video content
    NOTE: Only required if the video conveys content visually that is not available in the default audio track.

Guideline 1.3

Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure

Success Criteria WebAIM’s Recommendations
1.3.1 Info and Relationships
(Level A)
  • Semantic markup is used to designate headings (<h1>), lists (<ul>, <ol>, and <dl>), emphasized or special text (<strong>, <code>, <abbr>, <blockquote>, for example), etc. Semantic markup is used appropriately.
  • Tables are used for tabular data. Where necessary, data cells are associated with their headers. Data table captions and summaries are used where appropriate.
  • Text labels are associated with form input elements. Related form elements are grouped with fieldset/legend.
1.3.2 Meaningful Sequence
(Level A)
1.3.3 Sensory Characteristics
(Level A)
  • Instructions do not rely upon shape, size, or visual location (e.g., “Click the square icon to continue” or “Instructions are in the right-hand column”).
  • Instructions do not rely upon sound (e.g., “A beeping sound indicates you may continue.”).
1.3.4 Orientation
(WCAG 2.1
Level AA)
  • Orientation of web content is not restricted to only portrait or landscape, unless a specific orientation is necessary.
1.3.5 Identify Input Purpose
(WCAG 2.1
Level AA)

Guideline 1.4

Distinguishable: Make it easier for users to see and hear content including separating foreground from background

Success Criteria WebAIM’s Recommendations
1.4.1 Use of Color
(Level A)
  • Color is not used as the sole method of conveying content or distinguishing visual elements.
  • Color alone is not used to distinguish links from surrounding text unless the luminance contrast between the link and the surrounding text is at least 3:1 and an additional differentiation (e.g., it becomes underlined) is provided when the link is hovered over or receives focus.
1.4.2 Audio Control
(Level A)
  • A mechanism is provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds.
1.4.3 Contrast (Minimum)
(Level AA)
  • Text and images of text have a contrast ratio of at least 4.5:1.
  • Large text (over 18 point or 14 point bold) has a contrast ratio of at least 3:1
1.4.4 Resize text
(Level AA)
  • The page is readable and functional when the text size is doubled.
1.4.5 Images of Text
(Level AA)
  • If the same visual presentation can be made using text alone, an image is not used to present that text.
1.4.10 Reflow
(WCAG 2.1
Level AA)
  • No loss of content or functionality occurs and horizontal scrolling is avoided when content is presented at a width of 320 pixels.
    • This requires responsive design for most web sites. This is best tested by setting the browser window to 1280 pixels wide and then zooming the page content to 400%.
  • Content that requires horizontal scrolling, such as data tables, complex images (such as maps and charts), toolbars, etc. are exempted.
1.4.11 Non-text Contrast
(WCAG 2.1
Level AA)
  • A contrast ratio of at least 3:1 is present for differentiating graphical objects (such as icons and components of charts or graphs) and author-customized interface components (such as buttons, form controls, and focus indicators/outlines).
  • The various states (focus, hover, active, etc.) of author-customized interactive components must all present 3:1 contrast.
1.4.12 Text Spacing
(WCAG 2.1
Level AA)
  • No loss of content or functionality occurs when the user adapts text line height/spacing to 1.5 times the font size, paragraph spacing to 2 times the font size, word spacing to .16 times the font size, and letter spacing to .12 times the font size.
  • This is best supported by avoiding pixel height definitions for elements that contain text.
1.4.13 Content on Hover or Focus
(WCAG 2.1
Level AA)
  • When additional content is presented on hover or keyboard focus:
    • The newly revealed content can be dismissed (generally via the Esc key) without moving the pointer or keyboard focus, unless the content presents an input error or does not obscure or interfere with other page content.
    • The pointer can be moved to the new content without the content disappearing.
    • The new content must remain visible until the pointer or keyboard focus is moved away from the triggering control, the new content is dismissed, or the new content is no longer relevant.

Operable

Interface forms, controls, and navigation are operable

Guideline 2.1

Keyboard Accessible: Make all functionality available from a keyboard

Success Criteria WebAIM’s Recommendations
2.1.1 Keyboard
(Level A)
  • All page functionality is available using the keyboard, unless the functionality cannot be accomplished in any known way using a keyboard (e.g., free hand drawing).
  • Page-specified shortcut keys and accesskeys (accesskey should typically be avoided) do not conflict with existing browser and screen reader shortcuts.
2.1.2 No Keyboard Trap
(Level A)
  • Keyboard focus is never locked or trapped at one particular page element. The user can navigate to and from all navigable page elements using only a keyboard.
2.1.4 Character Key Shortcuts
(WCAG 2.1
Level A)
  • If a keyboard shortcut uses printable character keys, then the user must be able to disable the key command, change the defined key to a non-printable key (Ctrl, Alt, etc.), or only activate the shortcut when an associated interface component or button is focused.

Guideline 2.2

Enough Time: Provide users enough time to read and use content

Success Criteria WebAIM’s Recommendations
2.2.1 Timing Adjustable
(Level A)
  • If a page or application has a time limit, the user is given options to turn off, adjust, or extend that time limit. This is not a requirement for real-time events (e.g., an auction), where the time limit is absolutely required, or if the time limit is longer than 20 hours.
2.2.2 Pause, Stop, Hide
(Level A)
  • Automatically moving, blinking, or scrolling content that lasts longer than 3 seconds can be paused, stopped, or hidden by the user. Moving, blinking, or scrolling can be used to draw attention to or highlight content as long as it lasts less than 3 seconds.
  • Automatically updating content (e.g., automatically redirecting or refreshing a page, a news ticker, AJAX updated field, a notification alert, etc.) can be paused, stopped, or hidden by the user or the user can manually control the timing of the updates.

Guideline 2.3

Seizures: Do not design content in a way that is known to cause seizures

Success Criteria WebAIM’s Recommendations
2.3.1 Three Flashes or Below Threshold
(Level A)

Guideline 2.4

Navigable: Provide ways to help users navigate, find content, and determine where they are

Success Criteria WebAIM’s Recommendations
2.4.1 Bypass Blocks
(Level A)
  • A link is provided to skip navigation and other page elements that are repeated across web pages.
  • If a page has a proper heading structure, this may be considered a sufficient technique instead of a “Skip to main content” link. Note that navigating by headings is not yet supported in all browsers.
  • If a page uses frames and the frames are appropriately titled, this is a sufficient technique for bypassing individual frames.
2.4.2 Page Titled
(Level A)
  • The web page has a descriptive and informative page title.
2.4.3 Focus Order
(Level A)
  • The navigation order of links, form elements, etc. is logical and intuitive.
2.4.4 Link Purpose (In Context)
(Level A)
  • The purpose of each link (or form image button or image map hotspot) can be determined from the link text alone, or from the link text and it’s context (e.g., surrounding paragraph, list item, table cell, or table headers).
  • Links (or form image buttons) with the same text that go to different locations are readily distinguishable.
2.4.5 Multiple Ways
(Level AA)
  • Multiple ways are available to find other web pages on the site – at least two of: a list of related pages, table of contents, site map, site search, or list of all available web pages.
2.4.6 Headings and Labels
(Level AA)
  • Page headings and labels for form and interactive controls are informative. Avoid duplicating heading (e.g., “More Details”) or label text (e.g., “First Name”) unless the structure provides adequate differentiation between them.
2.4.7 Focus Visible
(Level AA)
  • It is visually apparent which page element has the current keyboard focus (i.e., as you tab through the page, you can see where you are).

Guideline 2.5

Input Modalities: Make it easier for users to operate functionality through various inputs beyond keyboard.

Success Criteria WebAIM’s Recommendations
2.5.1 Pointer Gestures
(WCAG 2.1
Level A)
  • If multipoint or path-based gestures (such as pinching, swiping, or dragging across the screen) are not essential to the functionality, then the functionality can also be performed with a single point activation (such as activating a button).
2.5.2 Pointer Cancellation
(WCAG 2.1
Level A)
  • To help avoid inadvertent activation of controls, avoid non-essential down-event (e.g., onmousedown) activation when clicking, tapping, or long pressing the screen. Use onclick, onmouseup, or similar instead. If onmouseup (or similar) is used, you must provide a mechanism to abort or undo the action performed.
2.5.3 Label in Name
(WCAG 2.1
Level A)
  • If an interface component (link, button, etc.) presents text (or images of text), the accessible name (label, alternative text, aria-label, etc.) for that component must include the visible text.
2.5.4 Motion Actuation
(WCAG 2.1
Level A)
  • Functionality that is triggered by moving the device (such as shaking or panning a mobile device) or by user movement (such as waving to a camera) can be disabled and equivalent functionality is provided via standard controls like buttons.
2.5.5 Target Size
(WCAG 2.1
Level AAA)
  • Clickable targets are at least 44 by 44 pixels in size unless an alternative target of that size is provided, the target is inline (such as a link within a sentence), the target is not author-modified (such as a default checkbox), or the small target size is essential to the functionality.
2.5.6 Concurrent Input Mechanisms
(WCAG 2.1
Level AAA)
  • Content does not restrict input to a specific modality, such as touch-only or keyboard-only, but must support alternative inputs (such as using a keyboard on a mobile device).

Understandable

Content and interface are understandable

Guideline 3.1

Readable: Make text content readable and understandable

Success Criteria WebAIM’s Recommendations
3.1.1 Language of Page
(Level A)
  • The language of the page is identified using the HTML lang attribute (<html lang=”en”>, for example).
3.1.2 Language of Parts
(Level AA)
  • The language of page content that is in a different language is identified using the lang attribute (e.g., <blockquote lang=”es”>).

Guideline 3.2

Predictable: Make Web pages appear and operate in predictable ways

Success Criteria WebAIM’s Recommendations
3.2.1 On Focus
(Level A)
  • When a page element receives focus, it does not result in a substantial change to the page, the spawning of a pop-up window, an additional change of keyboard focus, or any other change that could confuse or disorient the user.
3.2.2 On Input
(Level A)
  • When a user inputs information or interacts with a control, it does not result in a substantial change to the page, the spawning of a pop-up window, an additional change of keyboard focus, or any other change that could confuse or disorient the user unless the user is informed of the change ahead of time.
3.2.3 Consistent Navigation
(Level AA)
  • Navigation links that are repeated on web pages do not change order when navigating through the site.
3.2.4 Consistent Identification
(Level AA)
  • Elements that have the same functionality across multiple web pages are consistently identified. For example, a search box at the top of the site should always be labeled the same way.

Guideline 3.3

Input Assistance: Help users avoid and correct mistakes

Success Criteria WebAIM’s Recommendations
3.3.1 Error Identification
(Level A)
  • Required form elements or form elements that require a specific format, value, or length provide this information within the element’s label (or if a label is not provided, within the element’s title attribute).
  • If utilized, form validation errors are presented in an efficient, intuitive, and accessible manner. The error is clearly identified, quick access to the problematic element is provided, and user is allowed to easily fix the error and resubmit the form.
3.3.2 Labels or Instructions
(Level A)
  • Sufficient labels, cues, and instructions for required interactive elements are provided via instructions, examples, properly positioned form labels, and/or fieldsets/legends.
3.3.3 Error Suggestion
(Level AA)
  • If an input error is detected (via client-side or server-side validation), provide suggestions for fixing the input in a timely and accessible manner.
3.3.4 Error Prevention (Legal, Financial, Data)
(Level AA)
  • If the user can change or delete legal, financial, or test data, the changes/deletions can be reversed, verified, or confirmed.

Robust

Content can be used reliably by a wide variety of user agents, including assistive technologies

Guideline 4.1

Compatible: Maximize compatibility with current and future user agents, including assistive technologies

Success Criteria WebAIM’s Recommendations
4.1.1 Parsing
(Level A)
4.1.2 Name, Role, Value
(Level A)
  • Markup is used in a way that facilitates accessibility. This includes following the HTML/XHTML specifications and using forms, form labels, frame titles, etc. appropriately.
4.1.3 Status Messages
(WCAG 2.1
Level AA)
  • If an important status message is presented and focus is not set to that message, the message must be announced to screen reader users, typically via an ARIA alert or live region.
Date modified:
2020-08-30

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