@github/details-menu-element

<details-menu> element

A menu that's opened with a <details> button.

Installation

$ npm install @github/details-menu-element

Usage

import '@github/details-menu-element'

<details>
  <summary>Robots</summary>
  <details-menu>
    <ul>
      <li><button type="button" role="menuitem">Hubot</button></li>
      <li><button type="button" role="menuitem">Bender</button></li>
      <li><button type="button" role="menuitem">BB-8</button></li>
    </ul>
  </details-menu>
</details>

Use data-menu-button and data-menu-button-text to have button text updated on menu item activation.

<details>
  <summary>Preferred robot: <span data-menu-button>None</span></summary>
  <details-menu>
    <ul>
      <li><button type="button" role="menuitem" data-menu-button-text>Hubot</button></li>
      <li><button type="button" role="menuitem" data-menu-button-text>Bender</button></li>
      <li><button type="button" role="menuitem" data-menu-button-text>BB-8</button></li>
    </ul>
  </details-menu>
</details>

Use label[tabindex="0"][role=menuitemradio/menuitemcheckbox] when dealing with radio and checkbox inputs menu items. Check states of the input element and the label will be synchronized.

<details>
  <summary>Preferred robot</summary>
  <details-menu>
    <ul>
      <li><label tabindex="0" role="menuitemradio">
        <input type="radio" name="robot" value="Hubot"> Hubot
      </label></li>
      <li><label tabindex="0" role="menuitemradio">
        <input type="radio" name="robot" value="Bender"> Bender
      </label></li>
      <li><label tabindex="0" role="menuitemradio">
        <input type="radio" name="robot" value="BB-8"> BB-8
      </label></li>
    </ul>
  </details-menu>
</details>

Events

• details-menu-select - An item is to be select (cancelable).
• details-menu-selected - An item is selected, label updated, menu closed.

Deferred loading

Menu content can be loaded from a server by embedding an <include-fragment> element.

<details>
  <summary>Robots</summary>
  <details-menu src="/robots" preload>
    <include-fragment>Loading…</include-fragment>
  </details-menu>
</details>

The src attribute value is copied to the <include-fragment> the first time the <details> button is toggled open, which starts the server fetch.

If the preload attribute is present, the server fetch will begin on mouse hover over the <details> button, so the content may be loaded by the time the menu is opened.

Browser support

Browsers without native custom element support require a polyfill.

• Chrome
• Firefox
• Safari
• Internet Explorer 11
• Microsoft Edge

Development

npm install
npm test

License

Distributed under the MIT license. See LICENSE for details.