Node: getRootNode() method

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

Syntax

getRootNode()
getRootNode(options)

Parameters

options Optional

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

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

Return value

An object inheriting from Node. This will differ in exact form depending on where you called getRootNode(); for example:

  • Calling it on an element inside a standard web page will return an HTMLDocument object representing the entire page.
  • Calling it on an element inside a shadow DOM will return the associated ShadowRoot.

Examples

Example 1

The first simple example returns a reference to the HTML/document node:

const rootNode = node.getRootNode();

Example 2

This more complex example shows the difference between returning a normal root, and a root including the shadow root. 

<div class="parent">
  <div class="child"></div>
</div>
<div class="shadowHost">shadowHost</div>
<pre id="output">Output: </pre>

const parent = document.querySelector(".parent");
const child = document.querySelector(".child");
const shadowHost = document.querySelector(".shadowHost");
const output = document.getElementById("output");

output.textContent += `\nparent's root: ${parent.getRootNode().nodeName} \n`; // #document
output.textContent += `child's  root: ${child.getRootNode().nodeName} \n\n`; // #document

// create a ShadowRoot
const shadowRoot = shadowHost.attachShadow({ mode: "open" });
shadowRoot.innerHTML =
  '<style>div{background:#2bb8aa;}</style><div class="shadowChild">shadowChild</div>';
const shadowChild = shadowRoot.querySelector(".shadowChild");

// The default value of composed is false
output.textContent += `shadowChild.getRootNode() === shadowRoot : ${
  shadowChild.getRootNode() === shadowRoot
} \n`; // true
output.textContent += `shadowChild.getRootNode({composed:false}) === shadowRoot : ${
  shadowChild.getRootNode({ composed: false }) === shadowRoot
} \n`; // true
output.textContent += `shadowChild.getRootNode({composed:true}).nodeName : ${
  shadowChild.getRootNode({ composed: true }).nodeName
} \n`; // #document

Specifications

Specification
DOM Standard
# ref-for-dom-node-getrootnode①

Browser compatibility

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