HTML - <shadow>

The HTML <shadow> element is used as a shadow DOM insertion point. You might use it if you have created multiple shadow roots under a shadow host. It is not useful in ordinary HTML. It is used with Web Components.

Example

 

Here is a simple example of using the <shadow> element. It is an HTML file with everything needed in it.

Note: This is an experimental technology. For this code to work, the browser you display it in must support Web Components. See Enabling Web Components in Firefox.

HTML
<html>
  <head></head>
  <body>

  <!-- This <div> will hold the shadow roots. -->
  <div>
    <!-- This heading will not be displayed -->
    <h4>My Original Heading</h4>
  </div>

  <script>
    // Get the <div> above with its content
    var origContent = document.querySelector('div');
    // Create the first shadow root
    var shadowroot1 = origContent.createShadowRoot();
    // Create the second shadow root
    var shadowroot2 = origContent.createShadowRoot();

    // Insert something into the older shadow root
    shadowroot1.innerHTML =
      '<p>Older shadow root inserted by &lt;shadow&gt;</p>';
    // Insert into younger shadow root, including <shadow>.
    // The previous markup will not be displayed unless
    // <shadow> is used below.
    shadowroot2.innerHTML =
      '<shadow></shadow> <p>Younger shadow root, displayed because it is the youngest.</p>';
  </script>

  </body>
</html>

If you display this in a web browser it should look like the following.

shadow example

Description  

The HTML <shadow> element is used as a shadow DOM insertion point. You might use it if you have created multiple shadow roots under a shadow host. It is not useful in ordinary HTML. It is used with Web Components.

Content categories Transparent content.
Permitted content Flow content.
Tag omission None, both the starting and ending tag are mandatory.
Permitted parent elements Any element that accepts flow content.
DOM interface HTMLShadowElement

Browser Compatibility  

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 35 28 (28)[1] Not supported 26 Not supported
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 37 28.0 (28)[1] Not supported ? ?

[1] If Shadow DOM is not enabled in Firefox, <shadow> elements will behave like HTMLUnknownElement. Shadow DOM was first implemented in Firefox 33 and is behind a preference, dom.webcomponents.enabled, which is disabled by default.

See Also  

Specifications  

Specification Status Comment
Shadow DOM
The definition of 'shadow' in that specification.
Working Draft  

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/html/element/shadow

Element HTML Reference Web Components