ARIA property
aria-controls
Points at what this control operates. A combobox has to say what it opens.
It draws a line from a control to the thing that control drives, so assistive technology can offer a jump from one to the other. Change the ids and the line moves. Nothing on screen changes, because this describes a relationship rather than causing one.
Which roles may carry aria-controls
- Value
- ID reference 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-controls section of the ARIA specification.
Keeping aria-controls true
The failure here is silent by design. If the id it names is not in the document, the attribute is treated as absent rather than as broken, so a panel that only gets added to the page when it opens leaves this pointing at nothing the whole time it is shut. Nothing warns you, and the test rules deliberately skip it, on the reasoning that pointing at an element that does not exist and having no pointer at all come to the same end. So point at markup that is always there, and rewrite the ids whenever the thing being controlled is replaced rather than reused.
How aria-controls 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.
The value testing skips id references on purpose. Pointing at an element that does not exist and having no pointer at all come to the same end, so a broken reference fails no rule directly. It fails later, wherever the missing name or description was needed.
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-controls
- 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-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.
- aria-keyshortcuts Lists the keyboard shortcuts that activate this control, so they can be announced and checked for clashes.
Every ARIA state and property · Every ARIA role · ARIA explained