Accessibility Background

Web Content Accessibility Standards (WCAS) 2.1

The new ADA rules require that all digital content, and websites, and apps meet the International Web Content Accessibility Standards (WCAS) 2.1, which are found here: https://www.w3.org/TR/WCAG21/

4 Principles: (See also: Understanding the Four Principles of Accessibility)

Perceivable
Operable
Understandable
Robust

13 Guidelines:
13 guidelines provide the basic goals to make content more accessible to users with different disabilities.

Success Criteria:
For each guideline, testable success criteria are provided to allow WCAG 2.1 to be used where requirements and conformance testing are necessary such as in design specification, purchasing, regulation, and contractual agreements. In order to meet the needs of different groups and different situations, three levels of conformance are defined.

3 Levels of Conformance: (See also: Levels of Conformance)

A (lowest)
AA
AAA (highest)

2 Categories of Techniques:
(See also: Sufficient and Advisory Techniques in Understanding WCAG 2.1)

Sufficient - techniques that are sufficient for meeting the success criteria
Advisory - techniques that go beyond what is required by success criteria to better address the guidelines.

Principle 1: Perceivable

Principle 1: Perceivable
Information and user interface components must be presentable to users in ways they can perceive.

Guideline 1.1 Text Alternatives
Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.

1.1.1 Non-text Content
Level A - 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.)
TimeBased 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.

Guideline 1.2 Time-based Media
Provide alternatives for time-based media.

1.2.1 Audio-only and Video-only (Prerecorded)
1.2.2 Captions (Prerecorded)
1.2.3 Audio Description or Media Alternative (Prerecorded)
1.2.4 Captions (Live)
1.2.5 Audio Description (Prerecorded)
1.2.6 Sign Language (Prerecorded)
1.2.7 Extended Audio Description (Prerecorded)
1.2.8 Media Alternative (Prerecorded)
1.2.9 Audio-only (Live)

Guideline 1.3 Adaptable
Create content that can be presented in different ways (for example simpler layout) without losing information or structure.

1.3.1 Info and Relationships
1.3.2 Meaningful Sequence
1.3.3 Sensory Characteristics
1.3.4 Orientation
1.3.5 Identify Input Purpose
1.3.6 Identify Purpose

Guideline 1.4 Distinguishable
Make it easier for users to see and hear content including separating foreground from background.

1.4.1 Use of Color
1.4.2 Audio Control
1.4.3 Contrast (Minimum)
1.4.4 Resize Text
1.4.5 Images of Text
1.4.6 Contrast (Enhanced)
1.4.7 Low or No Background Audio
1.4.8 Visual Presentation
1.4.9 Images of Text (No Exception)
1.4.10 Reflow
1.4.11 Non-text Contrast
1.4.12 Text Spacing
1.4.13 Content on Hover or Focus

Principle 2: Operable

Principle 2. Operable
User interface components and navigation must be operable.

Guideline 2.1 Keyboard Accessible
Make all functionality available from a keyboard.

2.1.1 Keyboard
2.1.2 No Keyboard Trap
2.1.3 Keyboard (No Exception)
2.1.4 Character Key Shortcuts

Guideline 2.2 Enough Time
Provide users enough time to read and use content.

2.2.1 Timing Adjustable
2.2.2 Pause, Stop, Hide
2.2.3 No Timing
2.2.4 Interruptions
2.2.5 Re-authenticating
2.2.6 Timeouts
2.3 Seizures and Physical Reactions
2.3.1 Three Flashes or Below Threshold
2.3.2 Three Flashes
2.3.3 Animation from Interactions

Guideline 2.4 Navigable
Provide ways to help users navigate, find content, and determine where they are.

2.4.1 Bypass Blocks
2.4.2 Page Titled
2.4.3 Focus Order
2.4.4 Link Purpose (In Context)
2.4.5 Multiple Ways
2.4.6 Headings and Labels
2.4.7 Focus Visible
2.4.8 Location
2.4.9 Link Purpose (Link Only)
2.4.10 Section Headings

Guideline 2.5 Input Modalities
Make it easier for users to operate functionality through various inputs beyond keyboard.

2.5.1 Pointer Gestures
2.5.2 Pointer Cancellation
2.5.3 Label in Name
2.5.4 Motion Actuation
2.5.5 Target Size
2.5.6 Concurrent Input Mechanisms

Principle 3: Understandable

Principle 3 Understandable
Information and the operation of the user interface must be understandable.

Guideline 3.1 Readable
Make text content readable and understandable.

3.1.1 Language of Page
3.1.2 Language of Parts
3.1.3 Unusual Words
3.1.4 Abbreviations
3.1.5 Reading Level
3.1.6 Pronunciation

Guideline 3.2 Predictable
Make Web pages appear and operate in predictable ways.

3.2.1 On Focus
3.2.2 On Input
3.2.3 Consistent Navigation
3.2.4 Consistent Identification
3.2.5 Change on Request

Guideline 3.3 Input Assistance
Help users avoid and correct mistakes.

3.3.1 Error Identification
3.3.2 Labels or Instructions
3.3.3 Error Suggestion
3.3.4 Error Prevention (Legal, Financial, Data)
3.3.5 Help
3.3.6 Error Prevention (All)

Principle 4: Robust

Principle 4 Robust
Content must be robust enough that it can be interpreted 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.

4.1.1 Parsing
Level A - 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.

4.1.2 Name, Role, Value
Level A

4.1.3 Status Messages
Level AA