Node.getRootNode()

The getRootNode() property of the Node interface returns the context object's root, which optionally includes the shadow root if it is available.

Syntax

var root = node.getRootNode(options)

Parameters

options Optional

An object that sets options for getting the root node. The available options are:

• composed: A Boolean that indicates whether the shadow root should be returned (false, the default), or a root node beyond shadow root (true).

Returns

A Node interface.

Example

The first simple example will return a reference to the HTML/document node when run in supporting browsers:

rootNode = node.rootNode;

This more complex example shows the difference between returning a normal root, and a root incuding the shadow root:

<!-- source: https://github.com/jserz/js_piece/blob/master/DOM/Node/getRootNode()/demo/getRootNode.html -->
<div class="js-parent">
    <div class="js-child"></div>
</div>
<div class="js-shadowHost"></div>
<script>
    // work on Chrome 54+，Opera41+
    var parent = document.querySelector('.js-parent'),
        child = document.querySelector('.js-child'),
        shadowHost = document.querySelector('.js-shadowHost');
    console.log(parent.getRootNode().nodeName); // #document
    console.log(child.getRootNode().nodeName); // #document
    // create a ShadowRoot
    var shadowRoot = shadowHost.attachShadow({mode:'open'});
    shadowRoot.innerHTML = '<style>div{background:#2bb8aa;}</style>'
        + '<div class="js-shadowChild">content</div>';
    var shadowChild = shadowRoot.querySelector('.js-shadowChild');
    // The default value of composed is false
    console.log(shadowChild.getRootNode() === shadowRoot); // true
    console.log(shadowChild.getRootNode({composed:false}) === shadowRoot); // true
    console.log(shadowChild.getRootNode({composed:true}).nodeName); // #document
</script>

Specifications

Browser Compatibility