Control focus with tabindex

Rob Dodson

Alexandra Klepper

Standard HTML elements such as <button> or <input> have keyboard accessibility built in, and should be used whenever possible. However, if you need to build custom interactive elements, you can create the expected user behavior by adding tabindex.

Only add tabindex to content that is interactive. Even if content is important, such as a key image, screen reader users can understand it without adding focus.

What is tabindex?

In the occasion you need to modify the default tab order provided by built-in elements, you can use the tabindex HTML attribute to explicitly set an element's tab position.

tabindex can be applied to any element, though it should only be applied to interactive elements, and takes a range of integer values. With tabindex, you can specify an explicit order for focusable page elements, insert an otherwise unfocusable element into the tab order, and remove elements from the tab order. For example:

tabindex="0": Inserts an element into the natural tab order. The element can be focused by pressing Tab, and the element can be focused by calling its focus() method.

tabindex="-1": Removes an element from the natural tab order, but the element can still be focused by calling its focus() method

tabindex="5": Any tabindex greater than 0 brings that element to the front of the natural tab order. If there are multiple elements with a tabindex greater than 0, the tab order starts from the lowest value that is greater than zero and works its way up. Using a tabindex greater than 0 is considered an anti-pattern.

Ensure controls are keyboard accessible

A tool like Lighthouse is great at automatically detecting certain accessibility issues, however, some testing still must be manually done by a human.

Try pressing the Tab key to navigate through your site. Are you able to reach all the interactive controls on the page? If not, you may need to use tabindex to improve the focusability of those controls.

Manage focus at the page level

Sometimes, tabindex helps create seamless user experience. For example, if you build a robust single page with different content sections, where some content is hidden at different points in the page load. This could mean navigation links change the visible content, without a page refresh.

In this case, identify the selected content area and give it a tabindex of -1 and call its focus method. This ensures the content doesn't appear in the natural tab order. This technique, called managing focus, keeps the user's perceived context in sync with the site's visual content.

Manage focus in components

In some cases, you must also manage focus at the control level, such as with Custom Elements.

Knowing which keyboard behaviors to implement can be difficult. The Accessible Rich Internet Applications (ARIA) Authoring Practices guide lists types of components and what kinds of keyboard actions they support.

Insert an element into the tab order

Insert an element into the natural tab order using tabindex="0". For example:

<div tabindex="0">Focus me with the TAB key</div>

To focus an element, press the Tab key or call the element's focus() method.

Remove an element from the tab order

Remove an element using tabindex="-1". For example:

<button tabindex="-1">Can't reach me with the TAB key!</button>

This removes an element from the natural tab order, but the element can still be focused by calling its focus() method.

Applying tabindex="-1" to an element doesn't affect its children; if they're in the tab order naturally or because of a tabindex value, they'll remain in the tab order. To remove an element and all its children from the tab order, consider using the WICG's inert polyfill. The polyfill emulates the behavior of a proposed inert attribute, which prevents elements from being selected or read by assistive technologies.

Avoid tabindex > 0

Any tabindex greater than 0 jumps the element to the front of the natural tab order. If there are multiple elements with a tabindex greater than 0, the tab order starts from the lowest value greater than zero and works its way up.

Using a tabindex greater than 0 is considered an anti-pattern because screen readers navigate the page in DOM order, not tab order. If you need an element to come sooner in the tab order, it should be moved to an earlier spot in the DOM.

With Lighthouse, you can identify elements with a tabindex > 0. Run the Accessibility Audit (Lighthouse > Options > Accessibility) and look for the results of the "No element has a [tabindex] value greater than 0" audit.

Use "roving tabindex"

If you're building a complex component, you may need to add additional keyboard support beyond focus. When possible, use the built-in select element. It's focusable and allows for arrow keys to expose additional selectable options.

To implement similar functions in your own components, you can use a technique known as "roving tabindex". Roving tabindex works by setting tabindex to -1 for all children except the currently-active one. The component then uses a keyboard event listener to determine which key the user has pressed.

When this happens, the component sets the previously focused child's tabindex to -1, sets the to-be-focused child's tabindex to 0, and calls the focus() method on it.

Before

<div role="toolbar">
  <button tabindex="-1">Undo</button>
  <button tabindex="0">Redo</button>
  <button tabindex="-1">Cut</button>
</div>

After

<div role="toolbar">
  <button tabindex="-1">Undo</button>
  <button tabindex="-1">Redo</button>
  <button tabindex="0">Cut</button>
</div>

Keyboard access recipes

If you're unsure what level of keyboard support your custom components might need, you can refer to the ARIA Authoring Practices 1.1. This guide lists common UI patterns and identifies which keys your components should support.