What is tabbable?
The tabbable npm package is used to identify DOM elements that are tabbable or focusable. This is useful for accessibility concerns, such as when creating keyboard navigation or managing focus within modal dialogs, dropdowns, and custom widgets. It helps ensure that keyboard users can navigate through all interactive elements on the page in a logical order.
What are tabbable's main functionalities?
Finding all tabbable elements
This feature allows you to get a list of all elements that are tabbable (can be focused using the Tab key) within a specified DOM node.
var tabbable = require('tabbable');
var tabbableElements = tabbable(document);
console.log(tabbableElements);
Finding all focusable elements
This feature provides a list of all elements that are focusable, including those that are not tabbable but can still receive focus, such as elements with a tabindex='-1'. The option `{ includeContainer: true }` includes the container itself if it is focusable.
var tabbable = require('tabbable');
var focusableElements = tabbable(document, { includeContainer: true });
console.log(focusableElements);
Other packages similar to tabbable
focus-trap
The focus-trap package is designed to trap focus within a DOM element, preventing the user from tabbing out of it. This is particularly useful for modal dialogs. It is similar to tabbable in that it deals with focus management, but it provides a higher-level API specifically for creating a focus trap rather than just identifying focusable elements.
ally.js
ally.js is a JavaScript library that simplifies certain accessibility features, including focus management. It provides a broader range of accessibility utilities compared to tabbable, including the ability to find and manipulate focusable elements, but also extends to other areas such as accessible hiding of elements and maintaining disabled state across shadow DOM boundaries.
tabbable
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>
s<input>
s<select>
s<textarea>
s<a>
s with href
or xlink:href
attributes<audio>
s and <videos>
s with controls
attributes[contenteditable]
elements- anything with a non-negative
tabindex
Any of the above will not be considered tabbable, though, if any of the following are also true about it:
- negative
tabindex
disabled
- either the node itself or an ancestor of it is hidden via
display: none
or visibility: hidden
- it's an
<input type="radio">
and a different radio in its group is checked
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().
Installation
npm install tabbable
Dependencies: none.
You'll need to be compiling CommonJS (via browserify or webpack).
API
tabbable
tabbable(rootNode, [options])
Returns an array of ordered tabbable node 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.
rootNode
Type: Node
. Required.
options
includeContainer
Type: boolean
. Default: false
.
If set to true
, rootNode
will be included in the returned tabbable node array, if rootNode
is tabbable.
tabbable.isTabbable
tabbable.isTabbable(node)
Returns a boolean indicating whether the provided node is considered tabbable.
tabbable.isFocusable
tabbable.isFocusable(node)
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.
More details
- Tabbable tries to identify elements that are reliably tabbable across (not dead) browsers. Browsers are stupidly 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 that stupid 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>
s, <embed>
s, <object>
s, <summary>
s, and <svg>
s 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. - 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.
Feedback and contributions more than welcome!