Improvement of the ARIA implementation

[OlivierNourry]

Good to have implemented ARIA on the menu. Definitely makes a difference for screenreader users. I have tried different similar menus, and few even bother to care about this. It could be improved though: the opening button should have a role of button (on your demo page it's a link), which can be achieved preferably with a BUTTON element (role=button could make for it if a link must be kept for other reasons). You may refer to ARIA menubutton design pattern for detailed instructions on this.