HTML Guide for aria-activedescendant

The aria-activedescendant attribute on the input element must reference a non-empty, valid ID of an existing element.

The aria-activedescendant attribute is used in accessible widgets to indicate which element is currently active or selected within a composite widget, such as a listbox or autocomplete dropdown. Its value should be the id of an element within the DOM.

The attribute value must not be an empty string and must match the id of an existing element. Using an empty string ("") is invalid and triggers the W3C validator error.

Correct usage:

• Reference a valid, non-empty element id as the value.
• Remove the attribute if no element is currently active.

Example: Incorrect usage (invalid)

<input type="text" aria-activedescendant="" />

Example: Correct usage with a referenced ID

<ul id="suggestions">
  <li id="option1">Option 1</li>
  <li id="option2">Option 2</li>
</ul>
<input type="text" aria-activedescendant="option1" />

To eliminate errors, do not set aria-activedescendant to an empty string. Only include the attribute when it references a valid element’s id.