( function() {

	function addEventListeners() {
		document.addEventListener( 'change', handleChangeEvent );
		document.addEventListener( 'keydown', handleKeyDownEvent );
	}

	function handleChangeEvent( e ) {
		if ( 'INPUT' === e.target.nodeName && 'checkbox' === e.target.type && e.target.parentNode.classList.contains( 'frm_toggle_block' ) ) {
			handleToggleChangeEvent( e );
		}
	}

	function handleKeyDownEvent( e ) {
		switch ( e.key ) {
			case ' ':
				handleSpaceDownEvent( e );
				break;
		}
	}

	function handleToggleChangeEvent( e ) {
		e.target.nextElementSibling.setAttribute( 'aria-checked', e.target.checked ? 'true' : 'false' );
	}

	function handleSpaceDownEvent( e ) {
		if ( e.target.classList.contains( 'frm_toggle' ) ) {
			e.preventDefault(); // Prevent automatic browser scroll when space is pressed.
			e.target.click();
		}
	}

	addEventListeners();
}() );