The ariaPlaceholder property of the Element interface reflects the value of the aria-placeholder attribute, which defines a short hint intended to aid the user with data entry when the control has no value.

A string.

In this example the aria-placeholder attribute on the element with an ID of txtBoxInput has been set to a string. Using ariaPlaceholder we update the string to another value.

<div id="txtboxLabel">Enter your five-digit zipcode</div>
<div
  role="textbox"
  id="txtBoxInput"
  contenteditable="true"
  aria-placeholder="5-digit zipcode"
  aria-labelledby="txtboxLabel"></div>

let el = document.getElementById("txtBoxInput");
console.log(el.ariaPlaceholder); // "5-digit zipcode"
el.ariaPlaceholder = "12345";
console.log(el.ariaPlaceholder); // "12345"

• ARIA: textbox role