AHWD cheat sheet

WCAG 2.x is a W3C Recommendation; EN 301 549 is the European harmonised standard that incorporates WCAG for web content.

In the United States, ADA Title II (state/local government) and Title III (public accommodations) are enforced through litigation and DOJ guidance rather than a fixed technical rule set.

Section 508 applies to US federal agencies and their contractors; the Revised 508 standards (2018) incorporate WCAG 2.0 Level AA by reference.

ADA Title II final rule (2024) requires state and local governments to meet WCAG 2.1 Level AA for web content and mobile apps; compliance dates are staggered by population served.

The European Accessibility Act (EAA) covers specified products and services and applies from 28 June 2025; EN 301 549 is the presumed-conformance technical standard.

Conformance levels are A (minimum), AA (standard legal target), and AAA (enhanced, not generally mandated for whole sites).

WCAG success criteria are testable statements; the four principles are Perceivable, Operable, Understandable, Robust (POUR).

Accessibility statements and conformance claims must state the WCAG version, level, and scope of pages covered.

Disability categories relevant to design: visual, hearing, motor/physical, cognitive/learning, speech, and neurological; one person may have multiple.

The social model of disability locates barriers in the environment and design, not in the person's impairment.

The medical model frames disability as a defect to be treated; it leads to designs that fix the user rather than the interface.

POUR maps to user needs: Perceivable (senses), Operable (input methods), Understandable (cognition), Robust (assistive technology compatibility).

Inclusive design principle: recognize exclusion, learn from diversity, solve for one extend to many (Microsoft framework).

Situational and temporary limitations (bright sunlight, broken wrist, noisy room) share design solutions with permanent disabilities.

The curb-cut effect: accommodations built for disabled users (captions, keyboard access) benefit broader populations.

Person-first vs identity-first language is a preference; ask or follow the community's stated convention rather than assuming.

Text contrast minimum is 4.5:1 for normal text (SC 1.4.3); large text (18pt or 14pt bold) requires 3:1.

Non-text contrast (SC 1.4.11) requires 3:1 for UI components and graphical objects needed to understand content.

Every image needs an alt attribute; decorative images use alt="" so assistive technology skips them.

Form inputs require programmatically associated labels (label/for, aria-labelledby, or aria-label); placeholder text is not a label.

Keyboard operability (SC 2.1.1) means all functionality works from a keyboard; no keyboard trap (SC 2.1.2).

Focus visible (SC 2.4.7) requires an indicator; removing CSS outline without a replacement fails.

Page language must be set via the lang attribute on the html element (SC 3.1.1); language changes within content need their own lang.

Headings should be structured logically (h1-h6) without skipping levels for visual styling; use CSS for size.

Error identification (SC 3.3.1) requires text descriptions of input errors, not color alone.

Screen readers (NVDA, JAWS, VoiceOver, TalkBack) expose the accessibility tree built from DOM and ARIA.

The accessibility tree is derived from native semantics; correct HTML elements usually beat ARIA overrides.

First rule of ARIA: do not use ARIA if a native HTML element or attribute conveys the needed semantics.

aria-live regions announce dynamic content; polite waits for idle, assertive interrupts.

Screen magnification and reflow: content must work at 200% zoom (SC 1.4.4) and 400% reflow at 320 CSS px (SC 1.4.10).

Switch access and voice control rely on visible labels matching accessible names (SC 2.5.3 Label in Name).

Refreshable braille displays consume the same accessibility tree as screen readers.

Skip links and landmark regions let screen reader and keyboard users bypass repeated navigation.

Tagged PDFs carry structure (headings, lists, tables, reading order) that assistive technology reads; untagged PDFs are inaccessible.

PDF/UA (ISO 14289) is the standard for accessible PDF; verify with a checker plus manual reading-order review.

Word and other authoring tools export tags when built-in heading styles, lists, and alt text are used.

Tables in documents need header rows/columns marked and a table summary or caption where complex.

Prerecorded video with audio needs synchronized captions (SC 1.2.2); audio-only needs a transcript (SC 1.2.1).

Audio description (SC 1.2.5, Level AA) provides narration of visual information not conveyed by the main audio.

Captions should be accurate, synchronized, and identify speakers and meaningful sounds; auto-captions require review.

Document metadata: set a descriptive title in file properties so it appears in the title bar and assistive technology.

Automated tools detect roughly a third of WCAG issues; manual and assistive-technology testing are required for the rest.

Keyboard-only testing: tab through all interactive elements, confirm visible focus, logical order, and no traps.

Screen reader testing pairs a browser with a screen reader (e.g., NVDA + Firefox/Chrome, VoiceOver + Safari).

Contrast checkers compute the ratio (L1+0.05)/(L2+0.05) using relative luminance; verify against 4.5:1 or 3:1 thresholds.

Zoom and reflow testing: 200% zoom and 320px viewport width without two-dimensional scrolling.

Remediation priority: fix blockers (keyboard traps, missing labels, unreadable contrast) before cosmetic issues.

Accessibility conformance reports document scope, methods, tools, and known exceptions per WCAG criterion.

Regression testing should be added to CI so automated checks run on every build.