Co testujeme strojově, co částečně a co musí udělat člověk

Finds images, image buttons, SVGs and objects without a text alternative. Whether an existing alt text is accurate or an image is truly decorative needs a person.

image-alt · input-image-alt · object-alt · role-img-alt · svg-img-alt · aria-meter-name · aria-progressbar-name

Flags <audio> elements without a captions track. Transcripts placed elsewhere on the page are not detected.

audio-caption

Flags <video> elements without a captions track. Embedded players (YouTube, Vimeo) and open captions burned into the picture need a person.

video-caption

No automated test exists for the presence or quality of audio description.

Live media cannot be assessed by a page scan.

No automated test exists for audio description.

Finds broken lists, description lists, table header relationships and ARIA parent/child structures. Whether headings, landmarks and form groupings reflect the visual structure needs a person.

list · listitem · definition-list · dlitem · aria-required-children · aria-required-parent · td-has-header · td-headers-attr · th-has-data-cells · table-fake-caption · p-as-heading · aria-hidden-body

Reading order versus visual order is not machine-decidable.

Instructions that rely on shape, colour or position ("click the round button") need a person to spot.

Finds CSS that locks the page to one orientation. Scripts that do the same are not detected.

css-orientation-lock

Checks that autocomplete values are valid. Whether a field that should carry one is missing it needs a person.

autocomplete-valid

Finds links in running text that differ from the text by colour alone. Colour-only meaning in charts, forms and status needs a person.

link-in-text-block

Finds media that autoplays with sound for more than three seconds without controls.

no-autoplay-audio

Measures text contrast against solid backgrounds. Text over images, gradients or overlapping layers is set aside for a person to check.

color-contrast

Finds the viewport setting that blocks zooming. Whether the page still works at 200% needs a person.

meta-viewport

Whether an image contains text is not machine-decidable in this scanner.

Requires viewing the page at 320 CSS pixels wide; not part of the scan.

Contrast of icons, borders and controls is not measured.

Finds inline styles that prevent users from overriding text spacing. Whether content breaks when spacing is increased needs a person.

avoid-inline-spacing

Tooltip and popover behaviour needs interaction to assess.

Finds scroll areas and frames that keyboard users cannot reach. Custom controls that only work with a mouse need a person.

scrollable-region-focusable · frame-focusable-content · server-side-image-map

Keyboard traps only show when tabbing through the page.

Single-key shortcuts are not detectable from the page.

Finds pages that refresh or redirect on a timer. Session time-outs and countdowns in scripts need a person.

meta-refresh

Finds the blink and marquee elements. Carousels and animations need a person.

blink · marquee

Flashing content cannot be measured by a page scan.

Checks for a skip link, landmarks or headings. Whether the skip link actually works needs a person.

bypass

Finds pages without a title. Whether the title is descriptive is a judgement, but a missing one is certain.

document-title

Focus order needs tabbing through the page.

Finds links and image-map areas without any accessible name. Whether "read more" makes sense in context needs a person.

link-name · area-alt

Whether there is a second way to reach pages (search, sitemap, navigation) is a site-level judgement.

Descriptiveness of headings and labels is not machine-decidable.

Needs the page to be operated with a keyboard while watching the focus indicator.

Sticky headers and cookie bars covering the focused element only show when tabbing.

Multipoint and path gestures are not detectable from the page.

Down-event behaviour needs interaction to assess.

Finds controls whose accessible name does not contain their visible text.

label-content-name-mismatch

Motion-triggered functions are not detectable from the page.

Whether drag actions have a single-pointer alternative needs a person.

Measures whether targets meet 24×24 CSS pixels or have enough spacing. Inline links in text are exempt and skipped.

target-size

Finds a missing or invalid page language. Whether the declared language is the right one is a judgement, but a missing one is certain.

html-has-lang · html-lang-valid · html-xml-lang-mismatch

Checks that lang attributes on parts are valid. Passages in another language without a lang attribute need a person.

valid-lang

Context changes on focus need interaction to assess.

Context changes on input need interaction to assess.

Consistency across pages is a site-level judgement.

Consistency of components across pages is a site-level judgement.

Placement of help across pages is a site-level judgement.

Error messages only appear after submitting a form.

Finds fields with conflicting labels; fields without any name are reported under 4.1.2 (label, select-name). Whether instructions are sufficient needs a person.

form-field-multiple-labels

Only observable after submitting invalid input.

Confirmation and reversal steps in checkout need a person.

Repeated data entry across a process needs a person.

Cognitive tests in login flows need a person.

The broadest machine coverage: names of buttons, links, fields and frames, valid ARIA roles and attributes, hidden-but-focusable content, nested controls. Whether states (expanded, selected) are kept up to date by scripts needs a person.

button-name · link-name · label · select-name · input-button-name · input-image-alt · frame-title · frame-title-unique · summary-name · aria-allowed-attr · aria-required-attr · aria-roles · aria-valid-attr · aria-valid-attr-value · aria-prohibited-attr · aria-conditional-attr · aria-deprecated-role · aria-hidden-focus · aria-hidden-body · aria-command-name · aria-input-field-name · aria-tab-name · aria-toggle-field-name · aria-tooltip-name · aria-roledescription · aria-braille-equivalent · duplicate-id-aria · nested-interactive · area-alt

Whether status messages are announced needs interaction to assess.