aria-expanded must be used on elements with the role "button"

[masi]

Describe the bug In the examples <a> is used with aria-expaned but without role="button".

To Reproduce See documenation / web page.

Expected behavior

For proper a11y the aria-expanded attribute must be used on real buttons or elements with their role set to button. Either add role="button" in the examples or us <button> instead of <a>.

Note: a button must be able to be triggerd by hitting the space key.