Use fly-out (or drop-down) menus to provide an overview of a web site’s page hierarchy. It removes the need for multiple page loads provided that users know where to find the information. Application menus are usually implemented this way, too.
People with reduced dexterity, such as tremors, often have trouble operating fly-out menus. For some, it might be impossible. Make sure to provide other ways to the submenu items, for example by repeating them on the page of the parent menu item.
Indicate menu items with submenus visually and using markup. In the following example, the submenu is indicated visually by an icon and this WAI-ARIA markup:
aria-haspopup="true"declares that a menu item has a submenu.
aria-expanded="false"declares that the submenu is hidden.
The fly-out functionality is created using CSS and scripting with slightly separate considerations for mouse and keyboard users.
The following example uses this CSS code to show and hide the submenus when the parent menu items are hovered:
In addition, scripting is used to slightly delay the immediate closing of submenu items when the mouse leaves the area. This delay makes it easier to use the menu when navigation by a mouse is not very precise.
In the following example, a delay of one second is added using a timer:
Submenus should not open when using the tab key to navigate through the menu, as keyboard users would then have to step through all submenu items to get to the next top-level item. Instead, consider one of the following approaches.
Use parent as toggle
Use this approach in situations where the parent menu item only summarizes the submenu and doesn’t have to carry out a function, such as linking to a web page. In this case, the submenu is opened by a script when the user activates the top-level item and closed when the focus leaves the submenu.
Note: The value of the
The following code iterates through all top-level items with the class
has-submenu and adds a click event, which opens or closes the submenu depending on its state. Also, the
aria-expanded attribute is set to
true while the submenu is open, and to
Note: Despite the name, click events are activated regardless of the input method as soon as the link gets activated.
Use button as toggle
For situations when the parent menu item needs to carry out a function, such as linking to a web page, a separate button can be added to the parent item, to open and close the submenu. This button can also act as a visual indicator for the presence of a submenu.
The following code adds a button to every top-level menu item with a submenu. When the button is activated, it shows or hides the submenu. The invisible label of the button is set to “show submenu” or “hide submenu”, reflecting the state of the submenu.
Note: If possible, include the name of the parent menu item in the button label; for example: “show Space Bears submenu”.
Related WCAG 2.0 resources
These tutorials provide best-practice guidance on implementing accessibility in different situations. This page combined the following WCAG 2.0 success criteria and techniques from different conformance levels: