ARIA property
aria-colspan
How many columns a cell spans, when the markup cannot say so itself.
It widens a cell across the columns after it, so a header announces as covering the range it visually covers. Change the number and the cell's reach changes with it.
Which roles may carry aria-colspan
- Value
- integer
- Filed as
- A property, which is how ARIA files it and not a rule about how often it changes.
- Roles that may carry it
cell- Roles that inherit it
columnheader,rowheader
Those lists are not advice. Browsers are required to ignore a non-global attribute sitting on a role that does not support it, so aria-colspan on the wrong element is not weak, it is absent. You can read it in the DOM and nobody using a screen reader can.
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-colspan section of the ARIA specification.
Keeping aria-colspan true
Reach for this only where the host language has nothing to say. In an HTML table with a real colspan attribute, browsers are required to ignore the ARIA one and expose the HTML value instead, so setting both leaves you two numbers to keep in step and only one that counts. The value has to be one or more. Unlike aria-rowspan there is no zero shorthand here, so a cell running to the end of a group still has to name the number, and that number has to change when the group does.
How aria-colspan 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-colspan
- aria-colindex Which column a cell is in, counting from the real table rather than what is shown.
- aria-rowindex Which row this is, counting from the real table.
- aria-rowspan How many rows a cell spans, when the markup cannot say so.
Every ARIA state and property · Every ARIA role · ARIA explained