iron-collapse creates a collapsible block of content. By default, the content
will be collapsed. Use opened or toggle() to show/hide the content. The
aria-expanded attribute should only be set on the button that controls the
collapsable area, not on the area itself. See
https://www.w3.org/WAI/GL/wiki/Using_aria-expanded_to_indicate_the_state_of_a_collapsible_element#Description
iron-collapse adjusts the max-height/max-width of the collapsible element to show/hide
the content. So avoid putting padding/margin/border on the collapsible directly,
and instead put a div inside and style that.
<style>
.collapse-content {
padding: 15px;
border: 1px solid #dedede;
}
</style>
<iron-collapse>
<div class="collapse-content">
<div>Content goes here...</div>
</div>
</iron-collapse>The following custom properties and mixins are available for styling:
| Custom property | Description | Default |
|---|---|---|
--iron-collapse-transition-duration |
Animation transition duration | 300ms |
See: Documentation, Demo.
npm install --save @polymer/iron-collapse
<html>
<head>
<script type="module">
import '@polymer/iron-collapse/iron-collapse.js';
</script>
</head>
<body>
<iron-collapse id="collapse">
<div>Content goes here...</div>
</iron-collapse>
</body>
</html>import {PolymerElement, html} from '@polymer/polymer';
import '@polymer/iron-collapse/iron-collapse.js';
class SampleElement extends PolymerElement {
static get template() {
return html`
<iron-collapse id="collapse">
<div>Content goes here...</div>
</iron-collapse>
`;
}
}
customElements.define('sample-element', SampleElement);If you want to send a PR to this element, here are the instructions for running the tests and demo locally:
git clone https://github.com/PolymerElements/iron-collapse
cd iron-collapse
npm install
npm install -g polymer-clipolymer serve --npm
open http://127.0.0.1:<port>/demo/polymer test --npm