[](https://travis-ci.org/PolymerElements/iron-collapse)
_[Demo and API docs](https://elements.polymer-project.org/elements/iron-collapse)_
##<iron-collapse>
`iron-collapse` creates a collapsible block of content. By default, the content
will be collapsed. Use `opened` or `toggle()` to show/hide the content.
```html
Content goes here...
...
toggle: function() {
this.$.collapse.toggle();
}
```
`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.
```html
Content goes here...
```
### Styling
The following custom properties and mixins are available for styling:
| Custom property | Description | Default |
| --- | --- | --- |
| `--iron-collapse-transition-duration` | Animation transition duration | `300ms` |