A swup plugin for enhanced accessibility.
Loading new content via AJAX is a great experience for most users, but comes with serious shortcomings for screen reader users. This plugin will improve that:
- Announce page visits to screenreaders by reading the new page title
- Restore focus after swapping out the content
- Skip animations for users with a preference for reduced motion
Accessibility can be hard to get right. That's why we're keen to hear your feedback. Share your experience and suggest improvements by opening an issue on this repo. Let's make swup better together!
Install the plugin from npm and import it into your bundle.
npm install @swup/a11y-pluginimport SwupA11yPlugin from '@swup/a11y-plugin';Or include the minified production file from a CDN:
<script src="https://unpkg.com/@swup/a11y-plugin@5"></script>To run this plugin, include an instance in the swup options.
const swup = new Swup({
plugins: [new SwupA11yPlugin()]
});The plugin should work out of the box if you use proper semantic markup for your content, i.e. a
descriptive h1 for each page heading. See the options below for customizing what tags to look for.
<body> <!-- will be focused -->
<header>
Logo
</header>
<main>
<h1>Page Title</h1> <!-- will be announced -->
<p>Lorem ipsum dolor sit amet</p>
</main>
</body>The plugin will announce the new page to screen readers after navigating to it. It will look for the following and announce the first one found:
- Heading label:
<h1 aria-label="About"></h1> - Heading content:
<h1>About</h1> - Document title:
<title>About</title> - Page URL:
/about/
The easiest way to announce a page title differing from the main heading is using aria-label. The
example below will be announced as Homepage.
<h1 aria-label="Homepage">Project Title</h1>On page navigation, the plugin will reset focus to the body, imitating default browser behavior. When clicking anchor links on the same page, the plugin will focus the target of the link.
[!TIP] When linking to other sections on the page, make sure to target a single item that is descriptive of the section, e.g. a heading or a button. Linking to a large container has multiple issues: Some browsers will scroll to the center of the targeted container, disorienting near-sighted users with increased zoom. Screen readers will also start reading out the content of the targeted element, which can be overwhelming when a whole content section is being read out.
Browsers will display a visible outline around elements focused by this plugin. That's great for
orientation of keyboard users, but tends to be annoying for mouse users. We can make both groups of
users happy by using a combination of the :focus and :focus-visible pseudo-class to hide any
focus outlines while the site is being used with a mouse:
:focus:not(:focus-visible) {
outline: none;
}See these guides on Controlling focus and Styling focus for details and more examples.
All options with their default values:
{
headingSelector: 'h1',
respectReducedMotion: true,
autofocus: false,
announcements: {
visit: 'Navigated to: {title}',
url: 'New page at {url}'
}
}The selector for finding page headings. The content of the first found heading will be read to screenreaders after a new page was loaded.
Whether to respects users' preference for reduced motion.
Disable animated page transitions and animated scrolling if a user has enabled a setting on their device to minimize the amount of non-essential motion. Learn more about prefers-reduced-motion.
Whether to focus elements with an autofocus attribute after navigation.
[!CAUTION] Make sure to use this wisely. Automatically focussing elements can be useful to draw attention to inputs, but it comes with a list of drawbacks on its own, especially for screen-reading technology. See Autofocus accessibility considerations for details.
How the new page is announced. A visit is announced differently depending on whether the new page has a title or not. If found, the main heading or document title is announced. If neither is found, the new url will be announced instead:
-
Title found? Read
announcements.visit, replacing{title}with the new title -
No title? Read
announcements.visittoo, but replacing{title}with the content ofannouncements.url
{
announcements: {
visit: 'Navigated to: {title}',
url: 'New page at {url}'
}
}For multi-language sites, pass in a nested object keyed by locale. The locale must match the
html element's lang attribute
exactly. Use an asterisk * to declare fallback translations.
[!NOTE] Swup will not update the lang attribute on its own. For that, you can either install the Head Plugin to do it automatically, or you can do update it yourself in the
content:replacehook.
{
announcements: {
'en-US': {
visit: 'Navigated to: {title}',
url: 'New page at {url}'
},
'de-DE': {
visit: 'Navigiert zu: {title}',
url: 'Neue Seite unter {url}'
},
'fr-FR': {
visit: 'Navigué vers : {title}',
url: 'Nouvelle page à {url}'
},
'*': {
visit: '{title}',
url: '{url}'
}
}
}The plugin extends the visit object with a new a11y key that can be used to customize the
behavior on the fly.
{
from: { ... },
to: { ... },
a11y: {
announce: 'Navigated to: About',
focus: 'body'
}
}The text to announce after the new page was loaded. This is the final text after choosing the correct language from the announcements option and filling in any placeholders. Modify it to read a custom announcement.
Since the text can only be populated once the new page was fetched and its contents are available,
the only place to inspect or modify this would be right before the content:announce hook.
swup.hooks.before('content:announce', (visit) => {
visit.a11y.announce = 'New page loaded';
});The element to receive focus after the new page was loaded, by default the body. Can be customized
per visit. Set it to a selector string to select an element, or set it to false to not move the
focus on this visit.
The plugin adds two new hooks: content:announce and content:focus. Both run directly
after the internal content:replace handler, when the new content is already in the DOM.
Executes the announcement of the new page title.
swup.hooks.on('content:announce', () => console.log('New content was announced'));Executes the focussing of the new page.
swup.hooks.on('content:focus', () => console.log('New content received focus'));The plugin adds the following method to the swup instance:
Announce something programmatically. Use this if you are making use of
options.resolveUrl and still want
state changes to be announced.
swup.announce?.(`Filtered by ${myFilterString}`);