# Chrome 138
**Stable release date:** June 24th, 2025
Unless otherwise noted, the following changes apply to Chrome 138 stable
channel release for Android, ChromeOS, Linux, macOS, and Windows.
| Want just the highlights? Check out [New in Chrome 138](https://developer.chrome.com/blog/new-in-chrome-138).
## CSS and UI
### CSS Sign-Related Functions: `abs()`, `sign()`
The sign-related functions `abs()` and `sign()` compute various functions
related to the sign of their argument.
The `abs(A)` function contains one calculation A, and returns the absolute value
of A, as the same type as the input: if A's numeric value is positive or 0⁺,
just A again; otherwise -1 \* A.
The `sign(A)` function contains one calculation A, and returns -1 if A's numeric
value is negative, +1 if A's numeric value is positive, 0⁺ if A's numeric value
is 0⁺, and 0⁻ if A's numeric value is 0⁻. The return type is a ``, made
consistent with the type of the input calculation.
[MDN Docs:abs()](https://developer.mozilla.org/docs/Web/CSS/abs) \| [Tracking bug #40253181](https://issues.chromium.org/issues/40253181) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5091423843778560) \| [Spec](https://www.w3.org/TR/css-values-4/#sign-funcs)
### Interpolation progress functional notation: CSS `progress()` function
The `progress()` functional notation returns a `` value representing the
position of one calculation (the progress value) between two other calculations
(the progress start value and progress end value). The `progress()` function is
a math function.
[Tracking bug #40944203](https://issues.chromium.org/issues/40944203) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5112558941634560) \| [Spec](https://drafts.csswg.org/css-values-5/#progress)
### CSS `sibling-index()` and `sibling-count()`
The `sibling-index()` and `sibling-count()` functions can be used as integers in
CSS property values to style elements based on their position among its
siblings, or the total number of siblings respectively. These functions can be
used directly as integer values, but more interestingly inside `calc()`
expressions.
[Tracking bug #40282719](https://issues.chromium.org/issues/40282719) \| [ChromeStatus.com entry](https://chromestatus.com/feature/6225478530367488) \| [Spec](https://drafts.csswg.org/css-values-5/#tree-counting)
### CSS `stretch` sizing keyword
A keyword for CSS sizing properties (for example, `width` and `height`) that lets
elements grow to exactly fill their containing block's available space. It is
similar to '100%', except the resulting size is applied to the element's margin
box instead of the box indicated by `box-sizing`. Using this keyword lets the
element keep its margins while still being as large as possible. An
unprefixed version of `-webkit-fill-available`.
[Tracking bug #41253915](https://issues.chromium.org/issues/41253915) \| [ChromeStatus.com entry](https://chromestatus.com/feature/6176445286842368) \| [Spec](https://drafts.csswg.org/css-sizing-4/#sizing-values)
### CSS env variable for OS-level font scale
Exposes a user's preferred font scale to CSS. Without this, it's not practical for
a page to detect if the user has changed their preferred font size using the
Operating System's preferences. This CSS environment variable will reflect the
scale chosen by the user.
[Tracking bug #397737223](https://issues.chromium.org/issues/397737223) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5328467685801984) \| [Spec](https://drafts.csswg.org/css-env-1/#text-zoom)
## Devices
### Web serial over Bluetooth on Android
This feature lets web pages and web apps connect to serial ports over
Bluetooth on Android devices.
Chrome on Android now supports Web Serial API over Bluetooth RFCOMM. Existing
enterprise policies (`DefaultSerialGuardSetting`, `SerialAllowAllPortsForUrls`,
`SerialAllowUsbDevicesForUrls`, `SerialAskForUrls` and `SerialBlockedForUrls`) on
other platforms are enabled in future_on states for Android. All policies except
`SerialAllowUsbDevicesForUrls` will be enabled after the feature is enabled.
`SerialAllowUsbDevicesForUrls` will be enabled in a future launch after Android
provides system level support of wired serial ports.
[Tracking bug #375245353](https://issues.chromium.org/issues/375245353) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5139978918821888) \| [Spec](https://wicg.github.io/serial)
### Viewport Segments Enumeration API
The Viewport Segments API allows developers to adapt their web layout
to target foldable devices. The viewport segments defines the position and
dimensions of a logically separate region of the viewport. Viewport segments are
created when the viewport is split by one or more hardware features (such as a
fold or a hinge between separate displays) that act as a divider; segments are
the regions of the viewport that can be treated as logically distinct by the
developer.
[Tracking bug #1039050](https://issues.chromium.org/issues/1039050) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5170498990243840) \| [Spec](https://www.w3.org/TR/mediaqueries-5/#mf-horizontal-viewport-segments)
## JavaScript
### Update `QuotaExceededError` to a `DOMException` derived interface
Previously, when the web platform wants to tell you when you've exceeded quota,
it will use `DOMException` with the specific `name` property set to
`QuotaExceededError`. However this does not allow carrying additional
information.
This proposes removing "QuotaExceededError" from the list of built-in
`DOMException` names, and instead creates a class name `QuotaExceededError` from
the list of built-in `DOMException` and has the additional optional properties
`quota` and `requested`. We propose all instances of specs that throw
"QuotaExceededError" `DOMException`s get upgraded to instead throw
`QuotaExceededError`s. For now, such specs would leave the `quota` and
`requested` properties at their default value of `null`, but they could
eventually upgrade to include that data, if it's useful for their use case (and
isn't, e.g., a privacy leak).
[ChromeStatus.com entry](https://chromestatus.com/feature/6194847180128256) \| [Spec](https://github.com/whatwg/webidl/pull/1465)
## Web APIs
### Translator API
A JavaScript API to provide language translation capabilities to web pages.
Browsers are increasingly offering language translation to their users. Such
translation capabilities can also be useful to web developers. This is
especially the case when browser's built-in translation abilities cannot help.
An enterprise policy (`GenAILocalFoundationalModelSettings`) is available to
disable the underlying model downloading which would render this API
unavailable.
[MDN Docs](https://developer.mozilla.org/docs/Web/API/Translator) \| [Tracking bug #322229993](https://issues.chromium.org/issues/322229993) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5172811302961152) \| [Spec](https://webmachinelearning.github.io/translation-api)
### Language Detector API
A JavaScript API for detecting the language of text, with confidence levels.
An important supplement to translation is language detection. This can be
combined with translation, for example, taking user input in an unknown language and
translating it to a specific target language. Browsers today often already have
language detection capabilities, and we want to offer them to web developers
through a JavaScript API, supplementing the translation API. An enterprise
policy (`GenAILocalFoundationalModelSettings`) is available to disable the
underlying model downloading which would render this API unavailable.
[MDN Docs](https://developer.mozilla.org/docs/Web/API/LanguageDetector) \| [ChromeStatus.com entry](https://chromestatus.com/feature/6494349985841152) \| [Spec](https://webmachinelearning.github.io/translation-api/#language-detector-api)
### Summarizer API
Summarizer API is a JavaScript API for producing summaries of input text, backed
by an AI language model. Browsers and operating systems are increasingly
expected to gain access to a language model. By exposing this built-in model, we
avoid every website needing to download their own multi-gigabyte language model,
or send input text to third-party APIs. The summarizer API in particular exposes
a high-level API for interfacing with a language model in order to summarize
inputs for a variety of use cases (GitHub), in a way that does not depend on the
specific language model in question. An enterprise policy
(`GenAILocalFoundationalModelSettings`) is available to disable the underlying
model downloading which would render this API unavailable.
[MDN Docs](https://developer.mozilla.org/docs/Web/API/Summarizer) \| [Tracking bug #351744634](https://issues.chromium.org/issues/351744634) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5193953788559360) \| [Spec](https://webmachinelearning.github.io/writing-assistance-apis/#summarizer-api)
### Escape `<` and `>` in attributes on serialization
Escape `<` and `>` in values of attributes on serialization.
This mitigates the risk of mutation XSS attacks, which occur when value of an
attribute is interpreted as a start tag token after being serialized and
re-parsed.
[ChromeStatus.com entry](https://chromestatus.com/feature/6264983847174144) \| [Spec](https://github.com/whatwg/html/issues/6235)
### Crash Reporting API: `is_top_level` and `visibility_state`
This feature adds `is_top_level` and `visibility_state` string fields to the
crash reporting API body that gets sent to the default reporting endpoint for
crash reports.
[ChromeStatus.com entry](https://chromestatus.com/feature/5182880216776704) \| [Spec](https://github.com/WICG/crash-reporting/pull/23)
### Fire the `pushsubscriptionchange` event upon resubscription
Fire the `pushsubscriptionchange` event in service workers when an origin for
which a push subscription existed in the past, but which was revoked because of
a permission change (from granted to deny/default), is re-granted notification
permission.
The event will be fired with an empty oldSubscription and newSubscription.
[Tracking bug #407523313](https://issues.chromium.org/issues/407523313) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5147683423256576) \| [Spec](https://w3c.github.io/push-api/#the-pushsubscriptionchange-event)
## Multimedia
### Add support for video frame orientation metadata to WebCodecs
Introduces `rotation: int` and `flip: bool` values to various video related
interfaces in WebCodecs so that developers can work with frame sources that have
orientation (For example, Android cameras, certain media).
The `VideoFrame` interface grows the ability to create `VideoFrames` with arbitrary
rotation and flip as well as accessors for this information on the VideoFrame
object.
The `VideoDecoderConfig` object gains rotation and flip fields that are emitted on
decoded VideoFrame objects automatically.
The `VideoEncoder` class gains mechanisms for passing rotation and flip
information from `encode()` to the `VideoDecoderConfig` emitted as part of
`EncodedVideoChunkMetadata`. If `encode()` is called with frames with different
orientations a nonfatal exception will be thrown. `configure()` may be used to
reset the allowed orientation.
[Tracking bug #40243431](https://issues.chromium.org/issues/40243431) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5128855343595520) \| [Spec](https://www.w3.org/TR/webcodecs)
## Performance
### Add `prefetchCache` and `prerenderCache` to `Clear-Site-Data`header
Two new values for the `Clear-Site-Data` header to help developers target clearing
the prerender and prefetch cache: `"prefetchCache"` and `"prerenderCache"`.
[Tracking bug #398149359](https://issues.chromium.org/issues/398149359) \| [ChromeStatus.com entry](https://chromestatus.com/feature/4755745652080640) \| [Spec](https://wicg.github.io/nav-speculation/prefetch.html#clear-site-data-patches)
### Speculation rules: `target_hint` field
This extends speculation rules syntax to allow developers to specify the
target_hint field.
This field provides a hint to indicate a target navigable where a prerendered
page will eventually be activated. For example, when _blank is specified as a
hint, a prerendered page can be activated for a navigable opened by
window.open(). The field has no effect on prefetching.
The specification allows this field to accept any strings that are valid as
navigable target name or keyword as the value, but this launch supports only one
of `"_self"` or `"_blank"` strings. If the hint is not specified, it's treated like
`"_self"` is specified.
[Tracking bug #40234240](https://issues.chromium.org/issues/40234240) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5162540351094784) \| [Spec](https://wicg.github.io/nav-speculation/speculation-rules.html)
## Security
### Integrity Policy for scripts
Subresource-Integrity (SRI) enables developers to make sure the assets they
intend to load are indeed the assets they are loading. But there's no current
way for developers to be sure that all of their scripts are validated using SRI.
The `Integrity-Policy` header gives developers the ability to assert that every
resource of a given type needs to be integrity-checked. If a resource of that
type is attempted to be loaded without integrity metadata, that attempt will
fail and trigger a violation report.
[ChromeStatus.com entry](https://chromestatus.com/feature/5178394056327168) \| [Spec](https://github.com/w3c/webappsec-subresource-integrity/pull/133)
## Service Worker
### ServiceWorker support for Speculation Rules Prefetch
This feature enables ServiceWorker-controlled prefetches, that is a speculation
rules prefetch to URLs controlled by a Service Worker. Previously, the prefetch
is cancelled upon detecting a controlling Service Worker, thus subsequent
navigation to the prefetch target is served by the non-prefetch path. This
feature will enable the prefetch request to go through the Service Worker's
fetch handler and the response with the Service Worker interception is cached in
the prefetch cache, resulting in a subsequent navigation being served by the
prefetch cache. Use the enterprise policy
`PrefetchWithServiceWorkerEnabled` to control this feature.
[Tracking bug #40947546](https://issues.chromium.org/issues/40947546) \| [ChromeStatus.com entry](https://chromestatus.com/feature/4996410105397248) \| [Spec](https://wicg.github.io/nav-speculation/prefetch.html)
## Deprecations and removals
### WebGPU: Deprecate `GPUAdapter` `isFallbackAdapter` attribute
Deprecates the `GPUAdapter` `isFallbackAdapter` boolean attribute from WebGPU, which
is redundant with the `GPUAdapterInfo` `isFallbackAdapter` boolean attribute.
This upcoming removal is a minor breaking change as support for fallback
adapters has not yet been implemented in any browser, thereby resulting in both
`isFallbackAdapter` attributes consistently returning a falsy value.
[Tracking bug #409259074](https://issues.chromium.org/issues/409259074) \| [ChromeStatus.com entry](https://chromestatus.com/feature/4870179714236416) \| [Spec](https://github.com/gpuweb/gpuweb/pull/5099)
### Deprecate asynchronous range removal for Media Source Extensions
The Media Source standard long ago changed to disallow ambiguously defined
behavior involving asynchronous range removals:
- `SourceBuffer.abort()` no longer aborts `SourceBuffer.remove()` operations.
- Setting `MediaSource.duration` can no longer truncate currently buffered media.
Exceptions will be thrown in both of these cases now.
Safari and Firefox have long shipped this behavior, Chromium is the last browser
remaining with the old behavior. Use counters show that around 0.001%-0.005% of page loads
hit the deprecated behavior. If a site hits this
issue, playback may now break.
Usage of `abort()` cancelling removals is increasing, so it's prudent to resolve
this deprecation before more incompatible usage appears.
[Tracking bug #40474569](https://issues.chromium.org/issues/40474569) \| [ChromeStatus.com entry](https://chromestatus.com/feature/5190983595327488) \| [Spec](https://w3c.github.io/media-source)