What makes a website's navigation accessible?
Keyboard Input
Some people cannot use a mouse, including many older users with limited fine motor control. An accessible website does not rely on the mouse; it makes all functionality available from a keyboard. Then people with disabilities can use assistive technologies that mimic the keyboard, such as speech input.
How do I make my menu accessible?
Styling: Use commonly recognized design patterns to distinguish menus and the state of menu items. Fly-out Menus: Ensure fly-out (drop-down) submenus can be used appropriately by mouse and keyboard. Application Menus: Add specific markup and keyboard behavior to resemble desktop application menus.