The ariaMultiSelectable property of the Element interface reflects the value of the aria-multiselectable attribute, which indicates that the user may select more than one item from the current selectable descendants.

A string with one of the following values:

"true"

More than one item may be selected at a time.

"false"

Only one item may be selected.

In this example the aria-multiselectable attribute on the element with an ID of listbox1 is set to "true" indicating that this input accepts multiple selected items. Using ariaMultiSelectable we update the value to "false".

<div role="listbox" tabindex="0" id="listbox1"
  aria-multiselectable="true" aria-labelledby="listbox1label" aria-activedescendant="listbox1-1">
  <div role="option" id="listbox1-1" class="selected" aria-selected="true">Green</div>
  <div role="option" id="listbox1-2">Orange</div>
  <div role="option" id="listbox1-3">Red</div<
</div>

let el = document.getElementById("listbox1");
console.log(el.ariaMultiSelectable); // "true"
el.ariaMultiSelectable = "false";
console.log(el.ariaMultiSelectable); // "false"

• ARIA: listbox role