Makes me happy!
The aria-controls
                        attribute is used to create a relationship between the <button> and the
                        <div> that contains the content. It takes the idref of the
                        <div> as its value. This enables assistive technologies to provide specific
                        commands for moving focus from the <button> to the <div>.
                    
Note: at present there is little screen reader support for the
                        aria-controls attribute.
Makes me happy!