README.md

tabbable

Small utility that returns an array of all* tabbable DOM nodes within a containing node.

*all has some necessary caveats, which you'll learn about by reading below.

The following are considered tabbable:

• <button> elements
• <input> elements
• <select> elements
• <textarea> elements
• <a> elements with an href attribute
• <audio> and <video> elements with controls attributes
• the first <summary> element directly under a <details> element
• <details> element without a <summary> element
• elements with the [contenteditable] attribute
• anything with a non-negative tabindex attribute

Any of the above will not be considered tabbable, though, if any of the following are also true about it:

• has a negative tabindex attribute
• has a disabled attribute
• either the node itself or an ancestor of it is hidden via display: none (*see "Display check" below to modify this behavior)
• has visibility: hidden style
• is nested under a closed <details> element (with the exception of the first <summary> element)
• is an <input type="radio"> element and a different radio in its group is checked
• is a form field (button, input, select, textarea) inside a disabled <fieldset>

If you think a node should be included in your array of tabbables but it's not, all you need to do is add tabindex="0" to deliberately include it. (Or if it is in your array but you don't want it, you can add tabindex="-1" to deliberately exclude it.) This will also result in more consistent cross-browser behavior. For information about why your special node might not be included, see "More details", below.

Goals

• Accurate (or, as accurate as possible & reasonable)
• No dependencies
• Small
• Fast

Browser Support

Basically IE9+.

Why? It uses Element.querySelectorAll() and Window.getComputedStyle().

Note: When used with any version of IE, CSS.escape needs a polyfill for tabbable to work properly with radio buttons that have name attributes containing special characters.

Installation

npm install tabbable

API

tabbable

import { tabbable } from 'tabbable';

tabbable(rootNode, [options]);

• rootNode: Node (Required)
• options:
  • All the common options.
  • includeContainer: boolean (default: false)
    • If set to true, rootNode will be included in the returned tabbable node array, if rootNode is tabbable.

Returns an array of ordered tabbable nodes (i.e. in tab order) within the rootNode.

Summary of ordering principles:

• First include any nodes with positive tabindex attributes (1 or higher), ordered by ascending tabindex and source order.
• Then include any nodes with a zero tabindex and any element that by default receives focus (listed above) and does not have a positive tabindex set, in source order.

isTabbable

import { isTabbable } from 'tabbable';

isTabbable(node, [options]);

• node: Node (Required)
• options:
  • All the common options.

Returns a boolean indicating whether the provided node is considered tabbable.

focusable

import { focusable } from 'tabbable';

focusable(rootNode, [options]);

• rootNode: Node: Required
• options:
  • All the common options.
  • includeContainer: boolean (default: false)
    • If set to true, rootNode will be included in the returned focusable node array, if rootNode is focusable.

Returns an array of focusable nodes within the rootNode, in DOM order. This will not match the order in which tabbable() returns nodes.

isFocusable

import { isFocusable } from 'tabbable';

isFocusable(node, [options]);

• node: Node (Required)
• options:
  • All the common options.

Returns a boolean indicating whether the provided node is considered focusable.

💬 All tabbable elements are focusable, but not all focusable elements are tabbable. For example, elements with tabindex="-1" are focusable but not tabbable.

Common Options

These options apply to all APIs.

displayCheck option

Type: full | non-zero-area | none . Default: full.

Configures how to check if an element is displayed.

To reliably check if an element is tabbable/focusable, Tabbable defaults to the most reliable option to keep consistent with browser behavior, however this comes at a cost since every node needs to be validated as displayed using Web APIs that cause layout reflow.

For this reason Tabbable offers the ability of an alternative way to check if an element is displayed (or completely opt out of the check).

The displayCheck configuration accepts the following options:

• full: (default) Most reliably resembling browser behavior, this option checks that an element is displayed, which requires all of his ancestors are displayed as well (notice that this doesn't exclude visibility: hidden or elements with zero size). This option will cause layout reflow, however. If that is a concern, consider the none option.
  • ⚠️ If the container given to tabbable() or focusable(), or the node given to isTabbable() or isFocusable(), is not attached to the window's main document, the display check will default to "none" (see below for details) because the APIs used to determine a node's display are not supported unless it is attached (i.e. the browser does not calculate its display unless it is attached). This has effectively been tabbable's behavior for a very long time, and you may never have encountered an issue if the nodes with which you used tabbable were always displayed anyway (i.e. the "none" mode assumption was coincidentally correct).
  • You may encounter the above situation if, for example, you render to a node via React, and this node is not attached to the document (or perhaps, due to timing, it is not yet attached at the time you use tabbable's APIs).
• non-zero-area: This option checks display under the assumption that elements that are not displayed have zero area (width AND height equals zero). While not keeping true to browser behavior, this option may enhance accessibility, as zero-size elements with focusable content are considered a strong accessibility anti-pattern.
  • Like the full option, this option also causes layout reflow, and should have basically the same performance. Consider the none option if reflow is a concern.
  • ⚠️ As with the full option, there is a nuance in behavior depending on whether tabbable APIs are executed on attached vs detached nodes using this mode: Attached nodes that are actually displayed will be deemed visible. Detached nodes, even though displayed will always be deemed hidden because detached nodes always have a zero area as the browser does not calculate is dimensions.
• none: This completely opts out of the display check. This option is not recommended, as it might return elements that are not displayed, and as such not tabbable/focusable and can break accessibility. Make sure you know which elements in your DOM are not displayed and can filter them out yourself before using this option.

⚠️ Testing in JSDom (e.g. with Jest): See notes about testing in JSDom.

getShadowRoot option

By default, tabbable overlooks (i.e. does not consider) all elements contained in shadow DOMs (whether open or closed). This has been the behavior since the beginning.

Setting this option to a truthy value enables Shadow DOM support, which means tabbable will consider elements inside web components as candidates, both open (automatically) and closed (provided this function returns the shadow root).

Type: boolean | (node: FocusableElement) => ShadowRoot | boolean | undefined

• boolean:
  • true simply enables shadow DOM support for any open shadow roots, but never presumes there is an undisclosed shadow. This is the equivalent of setting getShadowRoot: () => false
  • false (default) disables shadow DOM support in so far as calculated tab order and closed shadow roots are concerned. If a child of a shadow (open or closed) is given to isTabbable() or isFocusable(), the shadow DOM is still considered for visibility and display checks.
• function:
  • node will be a descendent of the rootNode given to tabbable(), isTabbable(), focusable(), or isFocusable().
  • Returns: The node's ShadowRoot if available, true indicating a ShadowRoot is attached but not available (i.e. "undisclosed"), or a falsy value indicating there is no shadow attached to the node.

If set to a function, and if it returns true, Tabbable assumes a closed ShadowRoot is attached and will treat the node as a scope, iterating its children for additional tabbable/focusable candidates as though it was looking inside the shadow, but not. This will get tabbing order closer to -- but not necessarily the same as -- browser order.

Returning true from a function will also inform how the node's visibility check is done, causing tabbable to use the non-zero-area Display Check when determining if it's visible, and so tabbable/focusable.

More details

• Tabbable tries to identify elements that are reliably tabbable across (not dead) browsers. Browsers are inconsistent in their behavior, though — especially for edge-case elements like <object> and <iframe> — so this means some elements that you can tab to in some browsers will be left out of the results. (To learn more about this inconsistency, see this amazing table). To provide better consistency across browsers and ensure the elements you want in your tabbables list show up there, try adding tabindex="0" to edge-case elements that Tabbable ignores.
• (Exemplifying the above ^^:) The tabbability of <iframe>, <embed>, <object>, <summary>, and <svg> nodes is inconsistent across browsers, so if you need an accurate read on one of these elements you should try giving it a tabindex. (You'll also need to pay attention to the focusable attribute on SVGs in IE & Edge.) But you also might not be able to get an accurate read — so you should avoid relying on it.
• Radio groups have some edge cases, which you can avoid by always having a checked one in each group (and that is what you should usually do anyway). If there is no checked radio in the radio group, all of the radios will be considered tabbable. (Some browsers do this, otherwise don't — there's not consistency.)
• If you're thinking, "Why not just use the right querySelectorAll?", you may be on to something ... but, as with most "just" statements, you're probably not. For example, a simple querySelectorAll approach will not figure out whether an element is hidden, and therefore not actually tabbable. (That said, if you do think Tabbable can be simplified or otherwise improved, I'd love to hear your idea.)
• jQuery UI's :tabbable selector ignores elements with height and width of 0. I'm not sure why — because I've found that I can still tab to those elements. So I kept them in. Only elements hidden with display: none or visibility: hidden are left out. See "Display check" below for other options.
• Although Tabbable tries to deal with positive tabindexes, you should not use positive tabindexes. Accessibility experts seem to be in (rare) unanimous and clear consent about this: rely on the order of elements in the document.
• Safari on Mac OS X does not Tab to <a> elements by default: you have to change a setting to get the standard behavior. Tabbable does not know whether you've changed that setting or not, so it will include <a> elements in its list.

Help

Testing in JSDom

⚠️ JSDom is not officially supported. Your mileage may vary, and tests may break from one release to the next (even a patch or minor release).

This topic is just here to help with what we know may affect your tests.

Tabbable uses some DOM APIs such as Element.getClientRects() in order to determine node visibility, which helps in deciding whether a node is tabbable, focusable, or neither.

When using test engines such as Jest that use JSDom under the hood in order to run tests in Node.js (as opposed to using an automated browser testing tool like Cypress, Playwright, or Nightwatch where a full DOM is available), it is highly recommended (if not essential) to set the displayCheck option to none when calling any of the APIs in this library that accept it.

Using any other displayCheck setting will likely lead to failed tests due to nodes expected to be tabbable/focusable being determined to be the opposite because JSDom doesn't fully support some of the DOM APIs being used (even old ones that have been around for a long time).

You can globally overwrite the diplayCheck property by including this file in your __mocks__ folder:

// __mocks__/tabbable.js

const lib = jest.requireActual('tabbable');

const tabbable = {
   ...lib,
   tabbable: (node, options) => lib.tabbable(node, { ...options, displayCheck: 'none' }),
   focusable: (node, options) => lib.focusable(node, { ...options, displayCheck: 'none' }),
   isFocusable: (node, options) => lib.isFocusable(node, { ...options, displayCheck: 'none' }),
   isTabbable: (node, options) => lib.isTabbable(node, { ...options, displayCheck: 'none' }),
};

module.exports = tabbable;

Contributing

Feedback and contributions more than welcome!

See CONTRIBUTING.

Contributors

In alphabetical order:

Bryan Murphy 🐛 💻	Craig Kovatch 🐛	DaviDevMod 🐛 💻 ⚠️ 📖	David Clark 💻 🐛 🚇 ⚠️ 📖 🚧	Dependabot 🚧	Ido Rosenthal 🐛 💻 👀 ⚠️	Kristian Hamilton 🐛
Mateusz Burzyński 💻 🐛 📖	Richard Všianský 📖	Stefan Cameron 💻 🐛 🚇 ⚠️ 📖 🚧	Tyler Hawkins 🔧 ⚠️ 🚇 📖	bfrost 🐛	pebble2050 🐛