TYPO3 Accessibility (WCAG 2.2 AA)

Compatibility: TYPO3 v14.x (primary), v13.x, v12.4 LTS (fallbacks noted). All code works on v14. Version-specific fallbacks are marked with v12/v13:.

TYPO3 API First: Always use TYPO3's built-in APIs, Fluid ViewHelpers, and core features before adding custom markup. Verify methods exist in your target version.

PHP & JS over TypoScript: This skill provides PHP middleware, Fluid partials, and vanilla JavaScript solutions. TypoScript examples are avoided; use PHP-based approaches.

1. Accessibility Checklist (Go-Live Gate)

Run through this checklist before every deployment. Mark items as you fix them.

Semantic Structure

Every page has exactly one <h1>
Heading hierarchy is sequential (h1 > h2 > h3, no skips)
Landmark elements used: <main>, <nav>, <header>, <footer>, <aside>
Skip-to-content link is the first focusable element
<html lang="..."> matches page language
Language changes within content use lang attribute on containing element

Images & Media

All <img> have alt attribute (empty alt="" for decorative)
All <img> have explicit width and height (prevents CLS)
Complex images (charts, infographics) have long description
Videos have captions/subtitles
Audio content has transcript
No auto-playing media with sound

Color & Contrast

Text contrast >= 4.5:1 (normal) / 3:1 (large text >= 24px / 18.66px bold)
UI components and graphical objects >= 3:1 contrast
Information not conveyed by color alone (add icon, text, or pattern)
Dark mode (if implemented) maintains contrast ratios

Keyboard & Focus

All interactive elements reachable via Tab
Focus order matches visual order
Visible focus indicator on all interactive elements (:focus-visible)
No focus traps (except modals — which must trap correctly)
Escape closes modals/overlays and returns focus to trigger
Custom widgets have correct keyboard handlers

Forms

Every input has a programmatic <label> (explicit for/id or wrapping)
Placeholder is not used as sole label
Required fields indicated visually and with required attribute
Error messages linked to inputs via aria-describedby + aria-invalid
Form groups use <fieldset> + <legend>
Correct type and autocomplete attributes on inputs

ARIA & Dynamic Content

Icon-only buttons have aria-label
Decorative icons have aria-hidden="true"
Dynamic updates use aria-live="polite" or role="status"
Error alerts use role="alert"
Active navigation links have aria-current="page"
Expandable elements use aria-expanded

Motion & Interaction

prefers-reduced-motion respected (CSS and JS)
No content flashes more than 3 times per second
Touch targets >= 44x44 CSS pixels
user-scalable=no is NOT set in viewport meta

TYPO3-Specific

Backend: alt text fields are filled for all images in File List
Backend: content elements have descriptive headers (or header_layout = 100 for hidden)
Backend: page properties have proper <title> and description
Fluid templates use <f:link.page> / <f:link.typolink> (not <a> with manual hrefs)
Content Block / Content Element templates follow accessible patterns below

2. Fluid Template Patterns

2.1 Page Layout with Landmarks

<!-- EXT:site_package/Resources/Private/Layouts/Default.html -->
<f:layout name="Default" />

<f:render section="Main" />

<!-- EXT:site_package/Resources/Private/Templates/Default.html -->
<f:layout name="Default" />
<f:section name="Main">

<a href="#main-content" class="skip-link">
    <f:translate key="LLL:EXT:site_package/Resources/Private/Language/locallang.xlf:skip_to_content" />
</a>

<header role="banner">
    <nav aria-label="{f:translate(key: 'LLL:EXT:site_package/Resources/Private/Language/locallang.xlf:nav.main')}">
        <f:cObject typoscriptObjectPath="lib.mainNavigation" />
    </nav>
</header>

<main id="main-content">
    <f:render section="Content" />
</main>

<footer>
    <nav aria-label="{f:translate(key: 'LLL:EXT:site_package/Resources/Private/Language/locallang.xlf:nav.footer')}">
        <f:cObject typoscriptObjectPath="lib.footerNavigation" />
    </nav>
</footer>

</f:section>

2.2 Skip Link CSS

.skip-link {
    position: absolute;
    top: -100%;
    left: 0;
    z-index: 10000;
    padding: 0.75rem 1.5rem;
    background: var(--color-primary, #2563eb);
    color: var(--color-on-primary, #fff);
    font-weight: 600;
    text-decoration: none;
}
.skip-link:focus {
    top: 0;
}

2.3 Accessible Image Rendering

<!-- Partial: Resources/Private/Partials/Media/Image.html -->
<f:if condition="{image}">
    <figure>
        <f:image
            image="{image}"
            alt="{image.alternative}"
            title="{image.title}"
            width="{dimensions.width}"
            height="{dimensions.height}"
            loading="{f:if(condition: '{lazyLoad}', then: 'lazy', else: 'eager')}"
        />
        <f:if condition="{image.description}">
            <figcaption>{image.description}</figcaption>
        </f:if>
    </figure>
</f:if>

For decorative images (no informational value):

<f:image image="{image}" alt="" role="presentation" />

2.4 Accessible Content Element Wrapper

<!-- Partial: Resources/Private/Partials/ContentElement/Header.html -->
<f:if condition="{data.header} && {data.header_layout} != 100">
    <f:switch expression="{data.header_layout}">
        <f:case value="1"><h1>{data.header}</h1></f:case>
        <f:case value="2"><h2>{data.header}</h2></f:case>
        <f:case value="3"><h3>{data.header}</h3></f:case>
        <f:case value="4"><h4>{data.header}</h4></f:case>
        <f:case value="5"><h5>{data.header}</h5></f:case>
        <f:defaultCase><h2>{data.header}</h2></f:defaultCase>
    </f:switch>
</f:if>

2.5 Accessible Navigation Partial

<!-- Partial: Resources/Private/Partials/Navigation/MainMenu.html -->
<nav aria-label="{f:translate(key: 'LLL:EXT:site_package/Resources/Private/Language/locallang.xlf:nav.main')}">
    <ul role="list">
        <f:for each="{menu}" as="item">
            <li>
                <f:if condition="{item.active}">
                    <f:then>
                        <a href="{item.link}" aria-current="page">{item.title}</a>
                    </f:then>
                    <f:else>
                        <a href="{item.link}">{item.title}</a>
                    </f:else>
                </f:if>

                <f:if condition="{item.children}">
                    <ul>
                        <f:for each="{item.children}" as="child">
                            <li>
                                <a href="{child.link}"
                                   {f:if(condition: '{child.active}', then: 'aria-current="page"')}>
                                    {child.title}
                                </a>
                            </li>
                        </f:for>
                    </ul>
                </f:if>
            </li>
        </f:for>
    </ul>
</nav>

2.6 Accessible Accordion (Content Blocks / Custom CE)

<div class="accordion" data-accordion>
    <f:for each="{items}" as="item" iteration="iter">
        <div class="accordion__item">
            <h3>
                <button
                    type="button"
                    class="accordion__trigger"
                    aria-expanded="false"
                    aria-controls="accordion-panel-{data.uid}-{iter.index}"
                    id="accordion-header-{data.uid}-{iter.index}"
                    data-accordion-trigger
                >
                    {item.header}
                </button>
            </h3>
            <div
                id="accordion-panel-{data.uid}-{iter.index}"
                role="region"
                aria-labelledby="accordion-header-{data.uid}-{iter.index}"
                class="accordion__panel"
                hidden
            >
                <f:format.html>{item.bodytext}</f:format.html>
            </div>
        </div>
    </f:for>
</div>

2.7 Accessible Tab Component

<div class="tabs" data-tabs>
    <div role="tablist" aria-label="{f:translate(key: 'tabs.label')}">
        <f:for each="{items}" as="item" iteration="iter">
            <button
                type="button"
                role="tab"
                id="tab-{data.uid}-{iter.index}"
                aria-controls="tabpanel-{data.uid}-{iter.index}"
                aria-selected="{f:if(condition: '{iter.isFirst}', then: 'true', else: 'false')}"
                tabindex="{f:if(condition: '{iter.isFirst}', then: '0', else: '-1')}"
            >
                {item.header}
            </button>
        </f:for>
    </div>

    <f:for each="{items}" as="item" iteration="iter">
        <div
            role="tabpanel"
            id="tabpanel-{data.uid}-{iter.index}"
            aria-labelledby="tab-{data.uid}-{iter.index}"
            tabindex="0"
            {f:if(condition: '!{iter.isFirst}', then: 'hidden')}
        >
            <f:format.html>{item.bodytext}</f:format.html>
        </div>
    </f:for>
</div>

3. PHP: Accessibility Middleware & Helpers

3.1 Language Attribute Middleware (PSR-15)

Ensures <html lang="..."> is always correct based on site language config.

<?php

declare(strict_types=1);

namespace Vendor\SitePackage\Middleware;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use TYPO3\CMS\Core\Attribute\AsMiddleware;
use TYPO3\CMS\Core\Site\Entity\SiteLanguage;

#[AsMiddleware(
    identifier: 'vendor/site-package/accessibility-lang',
    after: 'typo3/cms-frontend/content-length-headers',
)]
final class AccessibilityLangMiddleware implements MiddlewareInterface
{
    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
    {
        $response = $handler->handle($request);

        $siteLanguage = $request->getAttribute('language');
        if (!$siteLanguage instanceof SiteLanguage) {
            return $response;
        }

        $contentType = $response->getHeaderLine('Content-Type');
        if (!str_contains($contentType, 'text/html')) {
            return $response;
        }

        $locale = $siteLanguage->getLocale();
        $langCode = $locale->getLanguageCode();
        $body = (string)$response->getBody();

        $body = preg_replace(
            '/<html([^>]*)lang="[^"]*"/',
            '<html$1lang="' . htmlspecialchars($langCode) . '"',
            $body,
            1
        );

        $response->getBody()->rewind();
        $response->getBody()->write($body);

        return $response;
    }
}

v12/v13 fallback: Register via Configuration/RequestMiddlewares.php instead of the #[AsMiddleware] attribute:

<?php
// Configuration/RequestMiddlewares.php (v12/v13)
return [
    'frontend' => [
        'vendor/site-package/accessibility-lang' => [
            'target' => \Vendor\SitePackage\Middleware\AccessibilityLangMiddleware::class,
            'after' => ['typo3/cms-frontend/content-length-headers'],
        ],
    ],
];

3.2 Image Alt Text Validation (PSR-14 Event)

Warn editors when images lack alt text:

<?php

declare(strict_types=1);

namespace Vendor\SitePackage\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Core\DataHandling\DataHandler;
use TYPO3\CMS\Core\Messaging\FlashMessage;
use TYPO3\CMS\Core\Messaging\FlashMessageService;
use TYPO3\CMS\Core\Type\ContextualFeedbackSeverity;
use TYPO3\CMS\Core\Utility\GeneralUtility;

#[AsEventListener(identifier: 'vendor/site-package/alt-text-check')]
final class ImageAltTextValidationListener
{
    public function __construct(
        private readonly FlashMessageService $flashMessageService,
    ) {}

    public function __invoke(\TYPO3\CMS\Core\DataHandling\Event\AfterRecordPublishedEvent|object $event): void
    {
        // For DataHandler processDatamap_afterDatabaseOperations hook style usage:
        // This can be adapted as a DataHandler hook or PSR-14 event depending on version.
    }

    public function processDatamap_afterDatabaseOperations(
        string $status,
        string $table,
        string|int $id,
        array $fieldArray,
        DataHandler $dataHandler,
    ): void {
        if ($table !== 'sys_file_metadata') {
            return;
        }

        if (empty($fieldArray['alternative'] ?? '')) {
            $message = GeneralUtility::makeInstance(
                FlashMessage::class,
                'Image is missing alt text. Please add descriptive alt text for accessibility (WCAG 1.1.1).',
                'Accessibility Warning',
                ContextualFeedbackSeverity::WARNING,
                true,
            );

            $this->flashMessageService
                ->getMessageQueueByIdentifier()
                ->addMessage($message);
        }
    }
}

$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['processDatamapClass'][]
    = \Vendor\SitePackage\EventListener\ImageAltTextValidationListener::class;

3.3 Accessible Fluid ViewHelper: SrOnly

Renders screen-reader-only text:

<?php

declare(strict_types=1);

namespace Vendor\SitePackage\ViewHelpers;

use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractTagBasedViewHelper;

final class SrOnlyViewHelper extends AbstractTagBasedViewHelper
{
    protected $tagName = 'span';

    public function initializeArguments(): void
    {
        parent::initializeArguments();
        $this->registerUniversalTagAttributes();
    }

    public function render(): string
    {
        $this->tag->addAttribute('class', 'sr-only');
        $this->tag->setContent($this->renderChildren());
        return $this->tag->render();
    }
}

/* CSS for sr-only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

Usage in Fluid:

{namespace sp = Vendor\SitePackage\ViewHelpers}
<button aria-label="{f:translate(key: 'button.close')}">
    <svg aria-hidden="true"><!-- icon --></svg>
    <sp:srOnly><f:translate key="button.close" /></sp:srOnly>
</button>

4. JavaScript: Accessible Widgets

4.1 Accordion

// EXT:site_package/Resources/Public/JavaScript/accordion.js
class AccessibleAccordion {
    constructor(container) {
        this.container = container;
        this.triggers = container.querySelectorAll('[data-accordion-trigger]');
        this.init();
    }

    init() {
        this.triggers.forEach((trigger) => {
            trigger.addEventListener('click', () => this.toggle(trigger));
            trigger.addEventListener('keydown', (e) => this.handleKeydown(e));
        });
    }

    toggle(trigger) {
        const expanded = trigger.getAttribute('aria-expanded') === 'true';
        const panelId = trigger.getAttribute('aria-controls');
        const panel = document.getElementById(panelId);

        trigger.setAttribute('aria-expanded', String(!expanded));
        panel.hidden = expanded;
    }

    handleKeydown(e) {
        const triggers = [...this.triggers];
        const index = triggers.indexOf(e.currentTarget);

        switch (e.key) {
            case 'ArrowDown':
                e.preventDefault();
                triggers[(index + 1) % triggers.length].focus();
                break;
            case 'ArrowUp':
                e.preventDefault();
                triggers[(index - 1 + triggers.length) % triggers.length].focus();
                break;
            case 'Home':
                e.preventDefault();
                triggers[0].focus();
                break;
            case 'End':
                e.preventDefault();
                triggers[triggers.length - 1].focus();
                break;
        }
    }
}

document.querySelectorAll('[data-accordion]').forEach((el) => new AccessibleAccordion(el));

4.2 Tabs

// EXT:site_package/Resources/Public/JavaScript/tabs.js
class AccessibleTabs {
    constructor(container) {
        this.tablist = container.querySelector('[role="tablist"]');
        this.tabs = [...this.tablist.querySelectorAll('[role="tab"]')];
        this.panels = this.tabs.map(
            (tab) => document.getElementById(tab.getAttribute('aria-controls'))
        );
        this.init();
    }

    init() {
        this.tabs.forEach((tab) => {
            tab.addEventListener('click', () => this.selectTab(tab));
            tab.addEventListener('keydown', (e) => this.handleKeydown(e));
        });
    }

    selectTab(selectedTab) {
        this.tabs.forEach((tab, i) => {
            const selected = tab === selectedTab;
            tab.setAttribute('aria-selected', String(selected));
            tab.tabIndex = selected ? 0 : -1;
            this.panels[i].hidden = !selected;
        });
        selectedTab.focus();
    }

    handleKeydown(e) {
        const index = this.tabs.indexOf(e.currentTarget);
        let next;

        switch (e.key) {
            case 'ArrowRight':
                next = (index + 1) % this.tabs.length;
                break;
            case 'ArrowLeft':
                next = (index - 1 + this.tabs.length) % this.tabs.length;
                break;
            case 'Home':
                next = 0;
                break;
            case 'End':
                next = this.tabs.length - 1;
                break;
            default:
                return;
        }
        e.preventDefault();
        this.selectTab(this.tabs[next]);
    }
}

document.querySelectorAll('[data-tabs]').forEach((el) => new AccessibleTabs(el));

4.3 Modal / Dialog

// EXT:site_package/Resources/Public/JavaScript/dialog.js
class AccessibleDialog {
    constructor(dialog) {
        this.dialog = dialog;
        this.previousFocus = null;
        this.init();
    }

    init() {
        this.dialog.addEventListener('keydown', (e) => {
            if (e.key === 'Escape') this.close();
            if (e.key === 'Tab') this.trapFocus(e);
        });

        this.dialog.addEventListener('click', (e) => {
            if (e.target === this.dialog) this.close();
        });
    }

    open() {
        this.previousFocus = document.activeElement;
        this.dialog.showModal();

        const firstFocusable = this.dialog.querySelector(
            'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
        );
        firstFocusable?.focus();
    }

    close() {
        this.dialog.close();
        this.previousFocus?.focus();
    }

    trapFocus(e) {
        const focusable = this.dialog.querySelectorAll(
            'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
        );
        const first = focusable[0];
        const last = focusable[focusable.length - 1];

        if (e.shiftKey && document.activeElement === first) {
            e.preventDefault();
            last.focus();
        } else if (!e.shiftKey && document.activeElement === last) {
            e.preventDefault();
            first.focus();
        }
    }
}

Use the native <dialog> element in Fluid:

<dialog id="my-dialog" aria-labelledby="dialog-title" aria-modal="true">
    <h2 id="dialog-title">{dialogTitle}</h2>
    <div>{dialogContent}</div>
    <button type="button" data-close-dialog>
        <f:translate key="button.close" />
    </button>
</dialog>

4.4 Reduced Motion Check

// EXT:site_package/Resources/Public/JavaScript/motion.js
const prefersReducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)');

function getTransitionDuration() {
    return prefersReducedMotion.matches ? 0 : 300;
}

prefersReducedMotion.addEventListener('change', () => {
    document.documentElement.classList.toggle('reduce-motion', prefersReducedMotion.matches);
});

if (prefersReducedMotion.matches) {
    document.documentElement.classList.add('reduce-motion');
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

4.5 Live Region Announcer

// EXT:site_package/Resources/Public/JavaScript/announcer.js
class LiveAnnouncer {
    constructor() {
        this.region = document.createElement('div');
        this.region.setAttribute('aria-live', 'polite');
        this.region.setAttribute('aria-atomic', 'true');
        this.region.classList.add('sr-only');
        document.body.appendChild(this.region);
    }

    announce(message, priority = 'polite') {
        this.region.setAttribute('aria-live', priority);
        this.region.textContent = '';
        requestAnimationFrame(() => {
            this.region.textContent = message;
        });
    }
}

window.liveAnnouncer = new LiveAnnouncer();

Usage: window.liveAnnouncer.announce('3 results found');

5. CSS: Focus & Contrast Essentials

/* EXT:site_package/Resources/Public/Css/accessibility.css */

/* Visible focus indicator */
:focus-visible {
    outline: 3px solid var(--focus-color, #2563eb);
    outline-offset: 2px;
}

:focus:not(:focus-visible) {
    outline: none;
}

/* Touch targets */
button, a, input, select, textarea, [role="button"] {
    min-height: 44px;
    min-width: 44px;
}

/* Ensure readable line height (WCAG 1.4.12) */
body {
    line-height: 1.6;
}

p + p {
    margin-top: 1em;
}

/* Max line length for readability */
.ce-bodytext, .frame-default .content {
    max-width: 75ch;
}

/* Scroll margin for anchored headings */
[id] {
    scroll-margin-top: 5rem;
}

/* Hover + focus parity */
a:hover, a:focus-visible,
button:hover, button:focus-visible {
    text-decoration: underline;
}

6. TYPO3-Specific Configuration

6.1 TCA: Require Alt Text on Images

Make the alt text field required in file metadata:

<?php
// Configuration/TCA/Overrides/sys_file_metadata.php

$GLOBALS['TCA']['sys_file_metadata']['columns']['alternative']['config']['required'] = true;

// v12/v13 fallback: use eval instead
// $GLOBALS['TCA']['sys_file_metadata']['columns']['alternative']['config']['eval'] = 'required';

6.2 TCA: Header Layout Options

Provide proper heading levels and a "hidden" option for content elements:

<?php
// Configuration/TCA/Overrides/tt_content.php

$GLOBALS['TCA']['tt_content']['columns']['header_layout']['config']['items'] = [
    ['label' => 'H1', 'value' => '1'],
    ['label' => 'H2', 'value' => '2'],
    ['label' => 'H3', 'value' => '3'],
    ['label' => 'H4', 'value' => '4'],
    ['label' => 'H5', 'value' => '5'],
    ['label' => 'Hidden', 'value' => '100'],
];
$GLOBALS['TCA']['tt_content']['columns']['header_layout']['config']['default'] = '2';

v12 fallback: Use numeric array keys [0] = label, [1] = value:

// v12 style
$GLOBALS['TCA']['tt_content']['columns']['header_layout']['config']['items'] = [
    ['H1', '1'],
    ['H2', '2'],
    ['H3', '3'],
    ['H4', '4'],
    ['H5', '5'],
    ['Hidden', '100'],
];

6.3 Form Framework: Accessible Forms (EXT:form)

# EXT:site_package/Configuration/Form/Overrides/AccessibleForm.yaml
TYPO3:
  CMS:
    Form:
      prototypes:
        standard:
          formElementsDefinition:
            Text:
              properties:
                fluidAdditionalAttributes:
                  autocomplete: 'on'
            Email:
              properties:
                fluidAdditionalAttributes:
                  autocomplete: 'email'
                  inputmode: 'email'
            Telephone:
              properties:
                fluidAdditionalAttributes:
                  autocomplete: 'tel'
                  inputmode: 'tel'

6.4 Content Security Policy: Allow Inline Focus Styles

If CSP is enabled, ensure focus styles via external CSS (not inline):

<?php
// No inline styles needed — use the external accessibility.css
// If you must add inline styles, extend CSP via PSR-14:

declare(strict_types=1);

namespace Vendor\SitePackage\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Core\Security\ContentSecurityPolicy\Directive;
use TYPO3\CMS\Core\Security\ContentSecurityPolicy\Event\PolicyMutatedEvent;
use TYPO3\CMS\Core\Security\ContentSecurityPolicy\HashValue;

#[AsEventListener(identifier: 'vendor/site-package/csp-accessibility')]
final class CspAccessibilityListener
{
    public function __invoke(PolicyMutatedEvent $event): void
    {
        if ($event->getScope()->type->isFrontend()) {
            // Prefer external CSS over extending CSP for inline styles
        }
    }
}

7. Testing & Tools

Automated Testing

Tool	Use
`axe-core` / `axe DevTools`	Browser extension for automated WCAG checks
`pa11y`	CLI accessibility testing for CI/CD
`Lighthouse`	Chrome DevTools audit (Accessibility score)
`WAVE`	Browser extension for visual feedback

Manual Testing Checklist

Keyboard only: Navigate entire page using Tab, Shift+Tab, Enter, Escape, Arrow keys
Screen reader: Test with VoiceOver (macOS), NVDA/JAWS (Windows)
Zoom: Verify layout at 200% and 400% zoom
Color: Use browser dev tools to simulate color blindness
Reduced motion: Enable prefers-reduced-motion: reduce in OS settings

Pa11y CI Integration

# Run against local DDEV instance
npx pa11y https://mysite.ddev.site --standard WCAG2AA --reporter cli

// .pa11yci.json
{
    "defaults": {
        "standard": "WCAG2AA",
        "timeout": 30000,
        "wait": 2000
    },
    "urls": [
        "https://mysite.ddev.site/",
        "https://mysite.ddev.site/contact",
        "https://mysite.ddev.site/news"
    ]
}

8. Accessibility Extensions

Extension	Purpose	v12	v13	v14
`typo3/cms-core`	Built-in ARIA, focus management	✓	✓	✓
`brotkrueml/schema`	Structured data (WebPage, Article)	✓	✓	✓
`wapplersystems/a11y`	Accessibility toolbar for frontend	✓	✓	—
`b13/container`	Accessible grid/container layouts	✓	✓	✓

9. WCAG 2.2 Quick Reference

Success Criterion	Level	TYPO3 Solution
1.1.1 Non-text Content	A	`alt` attribute on `<f:image>`, TCA required field
1.3.1 Info and Relationships	A	Semantic HTML in Fluid, `<fieldset>`/`<legend>`
1.3.5 Identify Input Purpose	AA	`autocomplete` attributes on form fields
1.4.1 Use of Color	A	Icons + text alongside color indicators
1.4.3 Contrast (Minimum)	AA	CSS variables with 4.5:1 ratio
1.4.4 Resize Text	AA	`rem` units, no `user-scalable=no`
1.4.10 Reflow	AA	Fluid/responsive layouts
1.4.11 Non-text Contrast	AA	3:1 for UI components
1.4.12 Text Spacing	AA	`line-height: 1.6`, flexible containers
2.1.1 Keyboard	A	Native elements, keyboard handlers
2.4.1 Bypass Blocks	A	Skip link
2.4.3 Focus Order	A	Logical DOM order
2.4.7 Focus Visible	AA	`:focus-visible` styles
2.4.11 Focus Not Obscured	AA	`scroll-margin-top`, no sticky overlaps
2.5.8 Target Size	AA	44x44px minimum
3.1.1 Language of Page	A	`<html lang>` via middleware
3.1.2 Language of Parts	AA	`lang` attribute on multilingual content
3.3.1 Error Identification	A	`aria-invalid`, `aria-describedby`
3.3.2 Labels or Instructions	A	`<label>` on every input
4.1.2 Name, Role, Value	A	ARIA attributes on custom widgets
4.1.3 Status Messages	AA	`aria-live` regions

10. Anti-Patterns (Flag These in Reviews)

Anti-Pattern	Fix
`<div onclick="...">`	Use `<button>`
`outline: none` without replacement	Use `:focus-visible` with custom outline
`placeholder` as sole label	Add `<label>` element
`tabindex > 0`	Use `tabindex="0"` or natural DOM order
`user-scalable=no` in viewport	Remove it
`font-size: 12px` (absolute)	Use `rem` units
Images without `alt`	Add `alt="..."` or `alt=""` for decorative
Color-only error indication	Add icon + text
`<a>` without `href` for action	Use `<button>`
Missing `lang` on `<html>`	Set via middleware or Fluid layout
Auto-playing video with sound	Add `muted` or remove `autoplay`
Skipped heading levels	Fix hierarchy

v14-Only Accessibility Changes

The following accessibility-related changes apply exclusively to TYPO3 v14.

Accessible Combobox Pattern [v14 only]

TYPO3 v14 introduces a new accessible combobox pattern (#106637) in the backend. When building custom backend UI widgets, use this pattern instead of custom autocomplete/dropdown implementations.

Native `<dialog>` Element [v14 only]

Backend modals migrated from Bootstrap Modal to native <dialog> element (#107443). The native dialog provides better accessibility out of the box:

Built-in focus trapping
Proper aria-modal semantics
Escape key handling
Inert background
No JavaScript framework dependency

Update any custom backend JavaScript that uses Modal.show() or Modal.confirm() from the Bootstrap-based API.

Fluid 5.0 Accessibility Impact [v14 only]

Fluid 5.0 strict typing means ViewHelper arguments must be correctly typed. This affects accessibility-related ViewHelpers:

tabindex attributes must be integers, not strings
Boolean ARIA attributes (aria-hidden, aria-expanded) must be proper booleans

Related Skills

web-design-guidelines - General web accessibility audit (non-TYPO3)
web-platform-design - WCAG 2.2, responsive design, forms
typo3-seo - SEO and structured data (overlaps with a11y for alt text, headings)
typo3-content-blocks - Accessible Content Element templates

Credits & Attribution

Accessibility patterns adapted from:

Vercel Web Interface Guidelines (MIT License)
Vercel Agent Skills: web-design-guidelines (MIT License)
Platform Design Skills: web-platform-design (MIT License)
W3C WAI-ARIA Authoring Practices
WCAG 2.2 Specification

Thanks to Netresearch DTT GmbH for their contributions to the TYPO3 community.