Semantisches HTML und zugängliche Namen

Semantic HTML & Accessible Names

Assistive technologies rely on the browser's accessibility tree — computed from HTML elements, attributes and ARIA — to convey role, accessible name, state/value and document structure (WCAG 4.1.2, 1.3.1, 2.4.6, 2.5.3). Always start from native HTML elements before reaching for ARIA.

1. Native HTML First vs. Custom Elements

• First Rule of ARIA: if a native HTML element or attribute provides the semantics and keyboard behavior you need, use it directly (<button type="button">, <a href="...">, <input>, <select>, <textarea>, <dialog>, <details>/<summary>, <table>, <fieldset>/<legend>).
• Button vs. Link:
  • Use <a href="..."> for navigation that changes the URL or moves to a document/section. An <a> without an href is not keyboard-focusable.
  • Use <button type="button"> for in-page actions (opening a dialog, toggling state, submitting/deleting, sorting a table column, triggering a menu).
• Never attach click handlers to bare <div>, <span> or <svg> without a native interactive element or full role, tabindex="0", Enter/Space keyboard handling and state synchronization.

2. Landmarks, Document Regions & Heading Hierarchy

Screen reader users navigate pages by jumping across landmarks and headings:

• Page landmarks: structure views with <header> (banner), <nav> (navigation), <main> (main, one visible per view), <aside> (complementary) and <footer> (contentinfo).
• Disambiguate multiple landmarks of the same type: give multiple <nav> or <section>/<aside> landmarks distinct accessible names via aria-label or aria-labelledby (without repeating "navigation" inside aria-label).
• Logical heading outline (<h1>–<h6>): provide a clear <h1> for the current view and nest <h2>–<h6> by logical containment rather than visual font size.

3. Accessible Name Computation & Label in Name

Follow the W3C Accessible Name and Description Computation priority order:

1. aria-labelledby (overrides all other name sources — references space-separated IDs, even if hidden).
2. aria-label (overrides visible text content inside the element).
3. Native host-language association (<label for="...">, <legend> for <fieldset>, <caption> for <table>, alt for <img>, subtree text for <button>/<a>).
4. Fallback attributes (title or placeholder — fragile, never use as primary label).

Critical Naming Rules

• WCAG 2.5.3 Label in Name: when a control has a visible text label, its accessible name must contain the visible text string (ideally starting with it) so voice-control users saying "Click Save changes" can activate it. Never put aria-label="Submit form" on a button whose visible text says Save changes.
• Icon-only controls: give every icon-only button or link a concise aria-label (or visually hidden text), with aria-hidden="true" focusable="false" on the inner <svg>.
• Repeating row/card actions: in lists or tables with repeated buttons (Edit, Delete), disambiguate via aria-label="Edit invoice #1042" or aria-labelledby combining the action and row identifier.

4. Honest States & Properties

• Synchronize states in real time: aria-expanded="true|false" on disclosures/menus, aria-pressed="true|false" on toggles, aria-selected="true|false" on tabs/options, aria-current="page|step" on active nav items, and disabled / aria-disabled="true" when unavailable.
• Never leave dangling IDs in aria-labelledby, aria-describedby, aria-controls or aria-owns when targets unmount.