role="caption"

What role="caption" means, and when to use it

Use caption for the visible title of a figure, table, grid or treegrid. It goes inside the thing it names, and the parent should point at it with aria-labelledby, which is what turns the visible title into the table's own name.

The HTML element behind role="caption"

A caption element inside a table and a figcaption inside a figure both carry this role, and both are wired up to their parent already.

Document structure roles describe how the content is organized

These roles describe the shape of the content rather than controls somebody operates. Headings, lists, tables, figures and paragraphs, so that assistive technology users can navigate by structure instead of reading straight through.

Nearly every one of them has an HTML element that means the same thing and needs no help. Reaching for the role instead is a step backwards, because the element brings its behavior with it and the role brings none. ARIA in HTML goes further and asks conformance checkers to flag a role that only restates what the element already said.

There is one honest exception to that. Some browsers drop a list's semantics when CSS removes the markers, and ARIA in HTML says a redundant role="list" on a ul is reasonable in exactly that case.

Where role="caption" sits in the model

Inherits from

section → structure → roletype

The name can come from

Nowhere. ARIA forbids naming this role at all.

The normative definition stays with the W3C, so it cannot go stale here. caption in the ARIA specification.

How a checker tests role="caption"

Getting this one wrong is easy to assume is a 4.1.2 Name, Role, Value problem, and mostly it is not. A role in the wrong container, or a container holding the wrong children, is tested against 1.3.1 Info and Relationships, which is Level A. A name written on a role that forbids one is checked against 1.3.1 Info and Relationships as well. These are the published test rules that apply.

• ARIA required context role
• ARIA global properties not used where prohibited
• Role attribute has valid value

The other structure roles

• application Hands every keystroke to your code instead of the screen reader. Use it only when nothing else will do.
• article A self-contained piece of content that still makes sense pulled out on its own.
• blockquote A quotation from somewhere else.
• cell One data cell in a table.
• code A fragment of computer code.
• columnheader A header cell that names its column.
• definition The meaning of a term.
• deletion Text that has been removed.
• directory A list of references, such as a table of contents. ARIA 1.2 deprecates it in favor of list.
• document Content meant to be read rather than operated, which puts screen readers back into reading mode.
• emphasis Text carrying stress emphasis, the meaning the em element has.
• feed A stream of articles that keeps loading more as somebody scrolls.
• figure An illustration with a caption, referred to from the text around it.
• generic The role a plain div or span already has. It exists for browsers, not for authors.
• group A set of related items that is not important enough to be a landmark and stays out of the page outline.
• heading A heading, which carries its level in aria-level rather than in the element name.
• img Anything built from markup that should be announced as a single image.
• insertion Text that has been added.
• list A list, which has to contain actual list items.
• listitem One entry in a list.
• math A mathematical expression.
• meter A gauge showing where a value sits in a known range, like disk usage. It is not a progress bar.
• none Strips an element's own meaning while leaving its content in place. The same role as presentation.
• note An aside or annotation about the content around it.
• paragraph A paragraph of text.
• presentation Strips an element's own meaning while leaving its content in place. The same role as none.
• row One row in a table, grid or treegrid.
• rowgroup A band of rows, the equivalent of thead or tbody.
• rowheader A header cell that names its row.
• separator A divider between sections. It becomes a control when it can be moved, and only then does it need a value.
• strong Text carrying strong importance, the meaning the strong element has.
• subscript Text set below the baseline.
• superscript Text set above the baseline.
• table Data laid out in rows and columns for reading, not for operating.
• term A word or phrase being defined.
• time A point in time or a length of it.
• toolbar A container for related controls that groups them for keyboard navigation.
• tooltip A small label that appears on hover or focus, and it should hold no controls of its own.