Features only in:
Chromium
Firefox
Safari

New features in Firefox for Android 147 (released on 2026-01-13)

Active view transition

Baseline Newly Available (since 2026-01-13)

The :active-view-transition CSS pseudo-class matches the root element when a view transition is active. The :active-view-transition-type() CSS pseudo-class matches only when the active view transition was started with the specified type.

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- Chrome 125 Released on 2024-05-14
- Chrome Android 125 Released on 2024-05-14
- Edge 125 Released on 2024-05-17
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 18.2 Released on 2024-12-11
- Safari on iOS 18.2 Released on 2024-12-11
CSS import attributes

Limited availability

Module import … with { type: "css" } statements load CSS modules as constructable stylesheets. Also known as CSS module scripts.

Baseline availability blocked since January 2026 by Safari (1 months)

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- Chrome 123 Released on 2024-03-19
- Chrome Android 123 Released on 2024-03-19
- Edge 123 Released on 2024-03-22
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari ❌ Vendor position : support
- Safari on iOS ❌ Vendor position : support
Iterator.concat()

Limited availability

The Iterator.concat() JavaScript method returns an iterator that yields values from a sequence of iterators, exhausting each iterator before moving on to the next.

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- Chrome ❌
- Chrome Android ❌
- Edge ❌
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari ❌
- Safari on iOS ❌
JavaScript modules in service workers

Baseline Newly Available (since 2026-01-13)

The navigator.serviceWorker.register() method accepts { type: "module" } to load scripts that use import and export. Also known as ECMAScript modules or ESM in service workers.

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- Chrome 91 Released on 2021-05-25
- Chrome Android 91 Released on 2021-05-25
- Edge 91 Released on 2021-05-27
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 15 Released on 2021-09-20
- Safari on iOS 15 Released on 2021-09-20
Navigation API

Baseline Newly Available (since 2026-01-13)

The navigation API initiates, intercepts, or modifies browser navigation actions. Not to be confused with the navigator API.

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- Chrome 102 Released on 2022-05-24
- Chrome Android 102 Released on 2022-05-24
- Edge 102 Released on 2022-05-31
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 26.2 Released on 2025-12-12
- Safari on iOS 26.2 Released on 2025-12-12
rcap unit

Baseline Newly Available (since 2026-01-13)

The rcap CSS length unit is a font-relative length equal to the value of the cap unit on the root element. Cap-height is approximately equal to the height of a capital Latin letter.

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- Chrome 118 Released on 2023-10-10
- Chrome Android 118 Released on 2023-10-10
- Edge 118 Released on 2023-10-13
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 17.2 Released on 2023-12-11
- Safari on iOS 17.2 Released on 2023-12-11
rch unit

Baseline Newly Available (since 2026-01-13)

The rch CSS length unit is a font-relative length equal to the value of the ch unit on the root element. ch length is based on the width of the zero (0) character.

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- Chrome 111 Released on 2023-03-07
- Chrome Android 111 Released on 2023-03-07
- Edge 111 Released on 2023-03-13
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 17.2 Released on 2023-12-11
- Safari on iOS 17.2 Released on 2023-12-11
rex unit

Baseline Newly Available (since 2026-01-13)

The rex CSS length unit is a font-relative length that is equal to the x-height of the root element.

Learn more
- Chrome 111 Released on 2023-03-07
- Chrome Android 111 Released on 2023-03-07
- Edge 111 Released on 2023-03-13
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 17.2 Released on 2023-12-11
- Safari on iOS 17.2 Released on 2023-12-11
ric unit

Baseline Newly Available (since 2026-01-13)

The ric CSS length unit, or root international character, is a font-relative length equal to the width of CJK character relative to the root element.

Learn more
- Chrome 111 Released on 2023-03-07
- Chrome Android 111 Released on 2023-03-07
- Edge 111 Released on 2023-03-13
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari 17.2 Released on 2023-12-11
- Safari on iOS 17.2 Released on 2023-12-11