# Vertical Navigation

Hierarchical, vertical navigation.

## Guidance

### When to use

- To display a navigational hierarchy with one to three levels.
- To display the “sub-navigation” within a section of the website.

### When to consider alternatives

- If the site has fewer than five pages, consider organizing the page without a navigational hierarchy.
- If your page already has a horizontal and vertical navigation bar, consider ways to simplify your navigation system.
- If your content is within a frame or sub-area of a page, consider ways to simplify your navigation system.

### Usage

- Indicate where a user is within the navigational hierarchy. Use the `.ds-c-vertical-nav__label--current` modifier to show users which page they have navigated to.
- Keep the navigation links short and follow sentence case. They can be shorter derivatives of page titles themselves.
- If the navigation hierarchy is too long, users may miss items at the bottom. If it’s too deep, users may miss items that require too many clicks. Usability test to find the right balance between breadth and depth.

## Accessibility

- If you have nested menus that are collapsible, the component automatically ensures that the `aria-controls` and `aria-expanded` attributes are set properly.
- If the site has fewer than five pages, consider organizing the page without a navigational hierarchy.
- When naming the optional `ariaNavLabel` prop, keep in mind:
  - This prop is necessary only when there is more than one `<nav>` element on a page. The Pagination component utilizes a `<nav>` element, so you will need to supply this prop on any page that includes both a Pagination and a VerticalNav component.
  - Don't include the word "Menu" in the label. Most screen readers will announce that already. Instead, provide more context about the menu’s contents or its location—such as "Main" or "Social".

## Accessibility testing

### Keyboard navigation

- Users must be able to tab through each link using a keyboard to navigate through the vertical navigation.
- Keyboard focus should not be trapped when navigating through vertical navigation links.
- When using a keyboard to move through the vertical navigation, there must be a visible outline or focus indicator showing where the focus is.

### Screen reader

- Screen readers must announce the vertical navigation region and its items.
- Screen readers must provide a direct description of links. When navigating to the vertical navigation with a screen reader, link titles must be read aloud and match the visible text on screen.
- Screen readers must announce each link’s title, visited state, hierarchy level (e.g., parent or submenu), and the number of links present. Screen readers will also announce whether an expandable submenu is open or collapsed.

## Learn more

- [Plain Language Guide: Headings (Digital.gov)](https://digital.gov/guides/plain-language/design/headings)