Web/API/CustomElementRegistry/upgrade

The upgrade() method of the CustomElementRegistry interface upgrades all shadow-containing custom elements in a Node subtree, even before they are connected to the main document.

Syntax

customElements.upgrade(root);

Parameters

root

A Node instance with shadow-containing descendant elements that are to be upgraded. If there are no descendant elements that can be upgraded, no error is thrown.

Return value

Void.

Examples

Taken from the HTML spec:

const el = document.createElement("spider-man");

class SpiderMan extends HTMLElement {}
customElements.define("spider-man", SpiderMan);

console.assert(!(el instanceof SpiderMan)); // not yet upgraded

customElements.upgrade(el);
console.assert(el instanceof SpiderMan);    // upgraded!

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'customElements.upgrade()' in that specification.	Living Standard	Initial definition.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
upgrade Experimental'	Chrome Full support 68	Edge Full support 79	Firefox Full support 63	IE No support No	Opera Full support 55	Safari ?	WebView Android Full support 68	Chrome Android Full support 68	Firefox Android Full support 63	Opera Android Full support 48	Safari iOS ?	Samsung Internet Android Full support 10.0

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

CustomElementRegistry.upgrade() by Mozilla Contributors is licensed under CC-BY-SA 2.5.