All posts
Accessibility 6 min read

The tab test: ten minutes to find out where your website breaks

Ten minutes, nothing to install, nothing to learn. The tab key shows you half the problems an audit would otherwise have to find.

Most accessibility reports come out of automated checks. Those are useful, but they only cover part of the ground: evaluation tools cannot determine accessibility, they can only assist, because some criteria require human judgement1. The rest sits exactly where one key on every keyboard will take you. This post walks through a check you can run yourself without any tooling, and says what it finds and what it does not.

Why the tab key of all things

People using a mouse look at the target and click it. People who do not use one move through the page in sequence. That focus order is set by the source, not by the layout. WCAG treats it as its own success criterion: the order has to preserve meaning and operability2.

Once source and layout diverge, the page becomes unusable without anything looking wrong in the design. And this is not only about permanent disability. A broken arm, a trackpad that has stopped tracking cleanly, or simply the habit of filling in forms from the keyboard: the group is considerably larger than the statistics suggest. The W3C explicitly counts temporary limitations such as a broken arm as part of who accessibility is for3.

If I cannot cross a page with the keyboard, the rest of the audit hardly matters.

The walkthrough

  1. Start at the very top

    Reload the page, click into the address bar, then press Tab once. The first jump should land on a link that skips the content, or on the first item in the navigation. Skip links are their own criterion in WCAG4.

  2. Keep pressing and keep watching

    Now Tab through. At every jump, ask two questions: can I see where I am? And is this the place that logically comes next?

  3. Open the menus

    On the menu button, press Enter or Space. Does the menu open? Does focus move into it? Does Escape get you back out? Being able to leave a region with the keyboard is explicitly required5.

  4. Fill in a form

    Complete and submit the contact form using only the keyboard. Introduce an error on purpose: is the error described? A detected input error has to be identified in text, not only marked in colour6.

  5. Back to the top

    Shift and Tab in reverse. Same order, the other way round. Anything skipped now, or stuck in a loop, is a finding.

What to watch for

  • Focus is clearly visible at every position, not merely inferable
  • The order follows what you see, top to bottom
  • Nothing lands behind an overlay or outside the visible area
  • Open menus and dialogs hold focus until they are closed
  • No element traps focus so that you cannot move on

The Austrian Accessibility Act has applied since 28 June 2025, implementing Directive (EU) 2019/882, known as the European Accessibility Act8. It covers online shops, booking flows, e-ticketing and banking services offered to consumers, among others9.

Microenterprises providing services are exempt. A microenterprise employs fewer than ten people and has either an annual turnover or a balance sheet total of no more than two million euros10. The line is less clear in practice than it sounds: the Austrian Economic Chamber gives the example of a business whose actual service is not named in the act at all, yet which is covered because its website lets customers book appointments and buy products. That makes it a service provided by electronic means9.

In practice: keyboard operability is no longer goodwill, it is a verifiable requirement. And it is the point where a check fails fastest.

What the test does not cover

The tab walkthrough finds operability problems. It says nothing about contrast, nothing about alternative text, and nothing about how the page is read aloud. WCAG groups its criteria under four principles11:

Perceivable

Content has to be available to every sense: alternative text, sufficient contrast, captions, scalable type.

Operable

Everything works without a mouse, with visible focus, enough time and no flashing that could trigger seizures.

Understandable

Plain language, predictable navigation, labelled form fields and error messages that say what to do.

Robust

Clean, semantic HTML so screen readers and assistive technology can interpret the page correctly.

The tab walkthrough covers the second pillar. That is a quarter of the work, but it is the quarter you can check yourself without tooling and without training.

What happens next

Write down every finding with the place it occurs. Two sentences is enough. Then sort by impact, not by effort: a checkout that cannot be operated weighs more than a focus problem in the footer.

Most of these findings can be fixed without a redesign. They are changes to markup and CSS, not rebuilds.

  • A tab walkthrough takes ten minutes and needs no tooling.
  • It finds the operability problems automated checks systematically miss.
  • Visible focus and a sensible order are the two things that matter most.
  • Contrast, alternative text and screen reader output need a separate look.
  • Most findings are markup and CSS changes, not a rebuild.

Sources

  1. W3C Web Accessibility Initiative, Evaluating Web Accessibility, section “Selecting Web Accessibility Evaluation Tools”.

  2. W3C, Web Content Accessibility Guidelines 2.1, success criterion 2.4.3 Focus Order.

  3. W3C Web Accessibility Initiative, Introduction to Web Accessibility. It names temporary disabilities such as a broken arm or lost glasses, and situational limitations, among others.

  4. W3C, Web Content Accessibility Guidelines 2.1, success criterion 2.4.1 Bypass Blocks.

  5. W3C, Web Content Accessibility Guidelines 2.1, success criterion 2.1.2 No Keyboard Trap.

  6. W3C, Web Content Accessibility Guidelines 2.1, success criterion 3.3.1 Error Identification.

  7. W3C, Web Content Accessibility Guidelines 2.1, success criterion 2.4.7 Focus Visible.

  8. Austrian Federal Ministry of Social Affairs, Barrierefreiheitsgesetz. Text of the act: BGBl. I No. 76/2023, RIS.

  9. Austrian Economic Chamber, Informationen zum Barrierefreiheitsgesetz.

  10. Sozialministeriumservice, Ausnahmen für Kleinstunternehmen, definition under § 6 (1) BaFG.

  11. W3C Web Accessibility Initiative, WCAG 2 Overview.

Check your website for free: load time, accessibility and SEO in two minutes

Read next

Why your website loads slowly Engineering4 min

A question about one of these topics? contact@primaris.at