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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The Element.attachShadow() method attaches a shadow DOM tree to the specified element and returns a reference to its ShadowRoot.


var shadowroot = element.attachShadow(shadowRootInit); 


ShadowRootInit dictionary, having the following field:

mode: A string specifying the encapsulation mode for the shadow DOM tree. One of:

  • open. Specifies open encapsulation mode.
    It means elements of the shadow root are accessible from an outside world using element.shadowRoot
    element.shadowRoot === shadowroot; // returns true
  • closed. Specifies closed encapsulation mode.
    This mode denies any access to node(s) of a closed shadow root from an outside world
    element.shadowRoot === shadowroot; // returns false
    element.shadowRoot === null; // returns true


Returns a ShadowRoot.


Specification Status Comment
The definition of 'attachShadow()' in that specification.
Living Standard  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 53.0 No support No support 43.0 10.0
Feature Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile
Basic support 53.0 53.0 No support ? ? ? ?

Document Tags and Contributors

 Last updated by: iamashish,