| CARVIEW |
Select Language
HTTP/2 200
x-guploader-uploadid: AAwnv3LTg_PeaFluHKDhyIJrggwJ2tkiSz9WCF1VL92uhXa02jn4KQP4-UtRtmyxAU6Gwol6
x-goog-generation: 1759972064823174
x-goog-metageneration: 1
x-goog-stored-content-encoding: identity
x-goog-stored-content-length: 164717
x-goog-meta-goog-reserved-file-mtime: 1759970595
x-goog-hash: crc32c=34zu9Q==, md5=eKyftNf+QZrWiENIHGNuEw==
x-goog-storage-class: STANDARD
accept-ranges: none
expires: Thu, 09 Oct 2025 08:34:14 GMT
cache-control: public, max-age=3600
last-modified: Thu, 09 Oct 2025 01:07:44 GMT
etag: W/"78ac9fb4d7fe419ad68843481c636e13"
content-type: text/html
age: 0
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
alt-svc: clear
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
strict-transport-security: max-age=63072000
content-security-policy: default-src 'self'; script-src 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; script-src-elem 'report-sample' 'self' 'wasm-unsafe-eval' https://www.google-analytics.com/analytics.js https://www.googletagmanager.com/gtag/js assets.codepen.io production-assets.codepen.io https://js.stripe.com 'sha256-XNBp89FG76amD8BqrJzyflxOF9PaWPqPqvJfKZPCv7M=' 'sha256-YCNoU9DNiinACbd8n6UPyB/8vj0kXvhkOni9/06SuYw=' 'sha256-PZjP7OR6mBEtnvXIZfCZ5PuOlxoDF1LDZL8aj8c42rw='; style-src 'report-sample' 'self' 'unsafe-inline'; object-src 'none'; base-uri 'self'; connect-src 'self' developer.allizom.org bcd.developer.allizom.org bcd.developer.mozilla.org updates.developer.allizom.org updates.developer.mozilla.org https://*.google-analytics.com https://*.analytics.google.com https://*.googletagmanager.com https://incoming.telemetry.mozilla.org https://observatory-api.mdn.allizom.net https://observatory-api.mdn.mozilla.net https://api.github.com/search/issues stats.g.doubleclick.net https://api.stripe.com; font-src 'self'; frame-src 'self' interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net mdn.github.io live-samples.mdn.mozilla.net live-samples.mdn.allizom.net *.mdnplay.dev *.mdnyalp.dev *.play.test.mdn.allizom.net https://v2.scrimba.com https://scrimba.com jsfiddle.net www.youtube-nocookie.com codepen.io survey.alchemer.com https://js.stripe.com; img-src 'self' data: *.githubusercontent.com *.googleusercontent.com *.gravatar.com mozillausercontent.com firefoxusercontent.com profile.stage.mozaws.net profile.accounts.firefox.com developer.mozilla.org mdn.dev interactive-examples.mdn.mozilla.net interactive-examples.mdn.allizom.net wikipedia.org upload.wikimedia.org https://mdn.github.io/shared-assets/ https://mdn.dev/ https://*.google-analytics.com https://*.googletagmanager.com www.gstatic.com; manifest-src 'self'; media-src 'self' archive.org videos.cdn.mozilla.net https://mdn.github.io/shared-assets/; child-src 'self'; worker-src 'self';
x-frame-options: DENY
origin-trial: AxVILwizhbMjxFeHOn1P3R8niO1RJY/smaK4B4d1rLzc1gTaxtXMSaTi+FoigYgCw40uFRDwFcEAeqDR+vVLOW4AAABfeyJvcmlnaW4iOiJodHRwczovL2RldmVsb3Blci5tb3ppbGxhLm9yZyIsImZlYXR1cmUiOiJQcml2YXRlQXR0cmlidXRpb25WMiIsImV4cGlyeSI6MTc0MjA3OTYwMH0=
x-cloud-trace-context: 653c8ae1f4d1c032f92ad3f39388f22f
date: Thu, 09 Oct 2025 07:34:14 GMT
server: Google Frontend
via: 1.1 google
vary: Accept-Encoding
content-encoding: gzip
x-cache: miss
HTML is global attribute - HTML | MDN
HTML is global attribute
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Note: Safari does not plan to support customized built-in elements and browser vendors are exploring alternative solutions to customizing built-ins. Check the browser compatibility section for support information.
The is global attribute allows you to specify that a standard HTML element should behave like a defined customized built-in element (see Using custom elements for more details).
This attribute can only be used if the specified custom element name has been successfully defined in the current document, and extends the element type it is being applied to.
Examples
The following code is taken from our word-count-web-component example (see it live also).
js
// Create a class for the element
class WordCount extends HTMLParagraphElement {
constructor() {
// Always call super first in constructor
super();
// Constructor contents omitted for brevity
// …
}
}
// Define the new element
customElements.define("word-count", WordCount, { extends: "p" });
html
<p is="word-count"></p>
Specifications
| Specification |
|---|
| HTML # attr-is |
Browser compatibility
Loading…
See also
- All global attributes.