systrace/catapult/third_party/polymer/components/paper-listbox/README.md


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[![Build status](https://travis-ci.org/PolymerElements/paper-listbox.svg?branch=master)](https://travis-ci.org/PolymerElements/paper-listbox)

_[Demo and API docs](https://elements.polymer-project.org/elements/paper-listbox)_


##&lt;paper-listbox&gt;

Material design: [Menus](https://www.google.com/design/spec/components/menus.html)

`<paper-listbox>` implements an accessible listbox control with Material Design styling. The focused item
is highlighted, and the selected item has bolded text.

```html
<paper-listbox>
  <paper-item>Item 1</paper-item>
  <paper-item>Item 2</paper-item>
</paper-listbox>
```

An initial selection can be specified with the `selected` attribute.

```html
<paper-listbox selected="0">
  <paper-item>Item 1</paper-item>
  <paper-item>Item 2</paper-item>
</paper-listbox>
```

Make a multi-select listbox with the `multi` attribute. Items in a multi-select listbox can be deselected,
and multiple item can be selected.

```html
<paper-listbox multi>
  <paper-item>Item 1</paper-item>
  <paper-item>Item 2</paper-item>
</paper-listbox>
```

### Styling

The following custom properties and mixins are available for styling:

| Custom property | Description | Default |
| --- | --- | --- |
| `--paper-listbox-background-color` | Menu background color | `--primary-background-color` |
| `--paper-listbox-color` | Menu foreground color | `--primary-text-color` |
| `--paper-listbox` | Mixin applied to the listbox | `{}` |

### Accessibility

`<paper-listbox>` has `role="listbox"` by default. A multi-select listbox will also have
`aria-multiselectable` set. It implements key bindings to navigate through the listbox with the up and
down arrow keys, esc to exit the listbox, and enter to activate a listbox item. Typing the first letter
of a listbox item will also focus it.