ARIA property
aria-multiline
Whether a text field takes more than one line, which changes what Enter does.
It sets the expectation for the Enter key. On a single-line field Enter submits. On a multiline one it inserts a line break, and this is how somebody finds that out before pressing it.
Which roles may carry aria-multiline
- Value
- true/false
- Filed as
- A property, which is how ARIA files it and not a rule about how often it changes.
- Roles that may carry it
textbox- Roles that inherit it
searchbox
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-multiline 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-multiline section of the ARIA specification.
Keeping aria-multiline true
Set once and left alone is usually right here, because a field rarely changes shape. What has to keep pace is the behaviour, since the attribute only reports a promise your key handler is making. A custom editor that grows into a rich text box while still saying false is telling people Enter will submit their half-written draft. And if you are using a real textarea you do not need this at all, because the element already says so. Adding it there only gives you a second place to be wrong.
How aria-multiline 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-multiline
- aria-activedescendant Points at the item inside a composite widget that is currently active, when focus stays on the container.
- aria-autocomplete How a text field predicts what you are typing.
- aria-errormessage Points at the message explaining why this field is invalid. Only meaningful while aria-invalid is set.
- aria-haspopup Says this control opens something, and what kind of thing it opens. A menu, a dialog, a listbox.
- aria-invalid Says a field's value has failed validation.
- aria-placeholder A hint shown in an empty field. It is not a label and does not replace one.
- aria-readonly The value can be read but not changed. Unlike disabled, it is still part of the form.
- aria-required Says a field has to be filled in before the form can be submitted.
Every ARIA state and property · Every ARIA role · ARIA explained