aria-posinset

The aria-posinset attribute defines an element's number or position in the current set of listitems or treeitems when not all items are present in the DOM.

Description

Short for "position in set", the aria-posinset attribute defines the position of the element within the whole set of listitems or treeitems when only a subset of the items are present in the DOM.

If all the items in a list are present in the DOM, the browser can calculate the total and the position of each, making aria-posinset unnecessary. When only a portion of a set is in the DOM, include aria-posinset to provide information about the element's position within the set along with aria-setsize to inform the user how many items are in the full set.

The following example shows a listbox with four element options out of the 118 in the periodic table of chemical elements.

<h2 id="periodictable">Periodic table of chemical elements</h2>
<ul role="listbox" aria-labelledby="periodictable">
  <li role="option" aria-setsize="118" aria-posinset="1">Hydrogen</li>
  <li role="option" aria-setsize="118" aria-posinset="3">Lithium</li>
  <li role="option" aria-setsize="118" aria-posinset="11">Sodium</li>
  <li role="option" aria-setsize="118" aria-posinset="19">Potassium</li>
</ul>

The value of each aria-posinset is an integer greater than or equal to 1, and less than or equal to the size of the set when that size is known.

Note: When using aria-posinset you must also include value for aria-setsize, which is the size of the entire set. If the size of the entire set is unknown, set aria-setsize="-1".

For menuitem, menuitemcheckbox, or menuitemradio, set the value of aria-posinset with respect to the total number of items in the menu, excluding any separators.

In a feed, each <article> element has aria-posinset set to a value that represents its position in the feed along with the aria-setsize set to either the number of articles that have been loaded or the total number in the feed, depending on which value is most helpful to users.

Values

<integer>

Integer greater than or equal to 1, and less than or equal to the value of aria-setsize.

ARIAMixin API

Element.ariaPosInSet

The ariaPosInSet property, part of the Element interface, reflects the value of the aria-posinset attribute.

ElementInternals.ariaPosInSet

The ariaPosInSet property, part of the ElementInternals interface, reflects the value of the aria-posinset attribute.

Associated roles

Specifications

Specification
Accessible Rich Internet Applications (WAI-ARIA)
# aria-posinset

See Also