ARIA property
aria-relevant
Which kinds of change in a live region are worth announcing.
It narrows what a live region reports. The default is additions and text, so nodes appearing and text changing get announced and removals do not. Add removals to the list and deletions start being reported as well.
Which roles may carry aria-relevant
- Value
- token list
- Filed as
- A property, which is how ARIA files it and not a rule about how often it changes.
- Roles that may carry it
- Any role. This one is global, which is why no individual role lists it.
Global means no role has to grant permission for it. There is one more place to check, because ARIA in HTML sets rules per element as well as per role, and it allows no aria-* attributes at all on a datalist or on the html element. Past that, the way a global attribute goes wrong is rarely where it sits. It is whether it is still true, which is the next section.
Every role above comes from the specification's own list for this attribute, checked name for name. The normative definition stays with the W3C, in the aria-relevant section of the ARIA specification.
Keeping aria-relevant true
The rule that catches people is that this does not merge. It inherits down the tree, and a value on a descendant replaces the inherited one outright instead of adding to it. So writing removals on a child does not leave you with additions, text and removals. It leaves you with removals and nothing else, which is how a chat log stops announcing new messages. Write the full list you want at every level you set it. And most regions do not need this at all, because the default is what people usually mean.
How aria-relevant gets checked
There are test rules that check an ARIA attribute is one that exists, is allowed on the role underneath it, and carries a value of the right type. What they map to is ARIA's own author requirements rather than any WCAG criterion, so a misplaced attribute breaks ARIA without being a WCAG failure by itself. It becomes one under 4.1.2 Name, Role, Value the moment the missing or wrong value means the control's state cannot be worked out programmatically, which is what usually happens next.
Nothing automated catches the failure this page is about. A stale value is a valid value, on a permitted role, with the right type. It is only wrong about the world.
Attributes you will meet alongside aria-relevant
- aria-atomic Whether an update should be read whole, or only the part that changed.
- aria-busy Says a region is still being updated, so wait before announcing it.
- aria-controls Points at what this control operates. A combobox has to say what it opens.
- aria-current Marks the one item in a set that represents the here and now, such as the current page in a nav.
- aria-describedby Points at further description, read after the name. Hints and error text usually go here.
- aria-details Points at richer explanation elsewhere in the page, which people can navigate to rather than have read out.
- aria-flowto Overrides reading order by pointing at what should be read next. Rarely the right answer.
- aria-hidden Removes an element from the accessibility tree while leaving it on screen.
Every ARIA state and property · Every ARIA role · ARIA explained