JarCasting
<iron-a11y-announcer>
iron-a11y-announcer is a singleton element that is intended to add a11y to features that require on-demand announcement from screen readers. In order to make use of the announcer, it is best to request its availability in the announcing element. Note: announcements are only audible if you have a screen reader enabled.
See: Documentation, Demo
Usage
Installation
npm install --save @polymer/iron-a11y-announcer
In an html file
<html>
<head>
<script type="module">
import {IronA11yAnnouncer} from '@polymer/iron-a11y-announcer/iron-a11y-announcer.js';
// Initialize the announcer.
IronA11yAnnouncer.requestAvailability();
// Note: announcements are only audible if you have a screen reader enabled.
IronA11yAnnouncer.instance.fire('iron-announce',
{text: 'Hello there!'}, {bubbles: true});
</script>
</head>
</html>
In a Polymer 3 element
import {PolymerElement, html} from '@polymer/polymer';
import {IronA11yAnnouncer} from '@polymer/iron-a11y-announcer/iron-a11y-announcer.js';
class SampleElement extends PolymerElement {
static get template() {
return html`
<button on-click="announce">Announce</button>
`;
}
function attached() {
IronA11yAnnouncer.requestAvailability();
}
// After the `iron-a11y-announcer` has been made available, elements can
// make announces by firing bubbling `iron-announce` events.
// Note: announcements are only audible if you have a screen reader enabled.
function announce() {
IronA11yAnnouncer.instance.fire('iron-announce',
{text: 'Hello there!'}, {bubbles: true});
}
}
customElements.define('sample-element', SampleElement);
Contributing
If you want to send a PR to this element, here are the instructions for running the tests and demo locally:
Installation
git clone https://github.com/PolymerElements/iron-a11y-announcer
cd iron-a11y-announcer
npm install
npm install -g polymer-cli
Running the demo locally
polymer serve --npm
open http://127.0.0.1:<port>/demo/
Running the tests
polymer test --npm
Known Issues
This element doesn't work on Firefox (it doesn't read anything in Voice Over), since aria-live has been broken since the Quantum redesign (see the MDN docs demo) -- we tested it on Firefox 60, but it doesn't look like a regression, so it's probably broken on older versions as well.
