F44Documented failure WCAG 2.4.3 Level A Human testing required

Do not break tab order with positive tabindex

The thing this failure names is not the attribute. F44 is a documented failure under the focus order rule, and what fails is a tab order that stops following the relationships in the content. A positive tabindex sequence that happens to match content order is not F44, which is why our method proves the finding by the jumping rather than by the attribute. That said, there is a reason to avoid positive values whatever your current order looks like, and it is the most useful thing on the published page. The commonest cause of this failure is editing. Somebody adds a field, or moves one, and does not renumber, so an order that was correct when it was written drifts out of step with the content it was numbered against. The rule itself is conditional. It applies where a page can be navigated in sequence and the sequence affects meaning or operation.

How we find it in an audit

Reviewers tab through the page from the top and write down where focus goes, in order, then hold that list next to the reading order. Any jump that changes meaning or breaks the task is the finding. Automated tools find positive tabindex values instantly and cannot tell you whether the resulting order is wrong, so a report flagging every positive value is listing candidates rather than defects. We look for gaps in the numbering as well, because that is usually where an edit happened.

How affected users experience it

A keyboard user builds a mental map of a form by tabbing through it, and expects each press to land somewhere sensible. When focus jumps from the name field to the promo code, back to email, then to a button, that map never forms. A screen reader user has it worse, because they are hearing the fields one at a time with no view of the whole, so an order that skips around is indistinguishable from a form missing fields. People submit forms with sections they never knew were there.

Passes vs. fails

Passes: focus follows the layout. Fails: focus teleports around the page.

Passes

<input id="name">
<input id="email">
<input id="promo-code">
<button>Submit</button>
<!-- Source order is the tab order, and it stays right after the next edit. -->

Fails

<input tabindex="2" id="name">
<input tabindex="4" id="email">
<input tabindex="1" id="promo-code">
<button tabindex="3">Submit</button>

The other techniques filed under this rule

8 guides on this site are filed under 2.4.3 Focus Order. W3C documents this one as a failure of that rule, so it describes a way the rule gets broken rather than a way to pass it.

This guide is our interpretation of W3C technique F44: Failure of Success Criterion 2.4.3 due to using tabindex to create a tab order that does not preserve meaning and operability. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.