Accessible Tabs

When you have a group of content items that you want to show users one at a time, a tablist is usually desired. Tablists is another common component on the web that does not have a native HTML5 implementation (i.e. there is no such thing as a <tablist> tag), although there is a group of people who are working to eventually get this in the HTML5 specification).

ARIA Tablist Example

This is the best solution to use, especially when building from scratch.

If you already are using a component similar to this in existing work that is not accessible, go to the developer walkthrough of this section to see we made our implementation accessible.

This solution described below is available as an NPM module. (Module installation instructions)

In order to make a tablist accessible, there are a few complications:

1. Technically, tablists are a list of items, and choosing one from a group should involve the arrow keys (like how users navigate a group of radio buttons)
2. Keyboard users may not know how this interaction works, and when they try to navigate through the tablist with a Tab key, they will be a bit confused when they skip over the whole list with one key press.
3. While you can give screen reader user verbal instructions about how to interact with a tablist, keyboard users that don't use a screen reader won't hear them.

In order to fix this UX issue, I show the instructions visually to keyboard users only. These instructions don't appear for mouse users. They also don't appear for mobile screen reader users who don't use a keyboard. Our implementation "borrows" their visual design, while adding our own code to conform to the W3C's recommended UX for a tablist (their implementation, unfortunately, doesn't seem to work with a keyboard with some screen reader/browser combinations, like VoiceOver for Safari on OSX).

This issue has been handled in differently in Danger! ARIA tabs, written by Jeff Smith (TL;DR: He decided to not code them using ARIA tabs, but as a list of links that anchor to the tabpanels).

Installation Instructions

You can load this JavaScript library into your application in serveral ways:

• as an ES6 module using Webpack.
• as a CommonJS module using require() and Webpack.
• as a native ES6 module within the browser.
• as an old-school ES4/JavaScript library.

If you haven't done so already, choosing which you should use is obviously a major architectural decision. Here are a few articles that will help you decide:

• Jan Olaf Krems gives a great overview of the JavaScript File Format Differences
• Joe Honton discusses that With ES Modules and HTTP/2 You May Not Need Webpack Anymore
• Stack Overflow has a really good thread about Webpack vs ES6 modules as well.

Using NPM/Webpack to load ES6 Modules:

1. Install the enable-a11y NPM project.
2. Edit your webpack.config.json file to resolve the ~ modifier by adding the following:
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   module.exports = { ... resolve: { extensions: ['.js', '.jsx', '.scss', '.css', '*.html'], modules: [ path.resolve('./src/js'), path.resolve('./node_modules') ], alias: { '~enable-a11y': path.resolve(__dirname, 'node_modules/enable-a11y') }, ... }, ... }
3. You can use the module like this:
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   // import the JS module import tabs from '~enable-a11y/js/modules/tabs'; // import the CSS for the module import '~enable-a11y/css/tabs'; // How to initialize the tabs library tabs.init(); // If you are adding a new instance of this component after page load, // then do the following (where el is the DOM node of the newly created // element, which contains the CSS class .enable-tablist): el.add();
4. Alternatively, if you are using LESS you can include the styles in your project's CSS using:
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   @import '~enable-a11y/css/tabs';
   (If you are using it in your CSS, you will have to add the .css suffix)

Using NPM/Webpack to Load Modules Using CommonJS Syntax

1. Install the enable-a11y NPM project.
2. You can import the module using require like this:
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   var tabs = require('enable-a11y/tabs').default; ... tabs.init();
3. You will have to include the CSS as well in your project's CSS using:
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   @import '~enable-a11y/css/tabs';

Using ES6 modules natively.

This is the method that this page you are reading now loads the scripts.

1. Grab the source by either using NPM, grabbing a ZIP file or cloning the enable source code from github.
2. If you want to load the module as a native ES6 module, copy js/modules/tabs.js , and css/tabs.css from the repo and put them in the appropriate directories in your project (all JS files must be in the same directory).
3. Load the CSS in the head of you document:
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   <html> <head> ... <link rel="stylesheet" href="path-to/css/tabs.css" > ... </head> <body> ... </body> </html>
4. Load your scripts using the follwing code (NOTE: you must use <script type="module">):
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   <script type="module"> import tabs from "path-to/tabs.js" tabs.init(); </script>

Using ES4