Web platform features explorer - Customized built-in elements

Customized built-in elements are HTML elements that extend built-in elements using the is attribute, to add new behaviors that you define.

Status

Limited availability

This feature received a negative standards position from at least one browser vendor. It's very unlikely to ever become Baseline in this current form.

MDN documentation

HTML is global attribute

Specifications

HTML (#customized-built-in-element), from HTML Workstream (WHATWG).

Browser support

Chrome 67 Released on 2018-05-29
Chrome Android 67 Released on 2018-05-31
Edge 79 Released on 2020-01-15
Firefox 63 Released on 2018-10-23
Firefox for Android 63 Released on 2018-10-23
Safari ❌ See webkit.org/b/182671 Vendor position : oppose
Safari on iOS ❌ See webkit.org/b/182671 Vendor position : oppose

Baseline availability blocked since January 2020 by Safari (66 months)

Web Platform Tests (WPT)

View the latest WPT test results for this feature

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