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Microsoft Edge 152 web platform release notes (Aug. 2026)

The following are the new web platform features and updates in Microsoft Edge 152, which releases on Aug. 27, 2026.

To stay up-to-date and get the latest web platform features, download a preview channel of Microsoft Edge (Beta, Dev, or Canary); go to Become a Microsoft Edge Insider.

Detailed contents:

Microsoft Edge DevTools

See What's new in Microsoft Edge DevTools.

WebView2

See Release notes for the WebView2 SDK.

CSS features

The following new Cascading Style Sheets (CSS) features are included in Microsoft Edge.

CSS alpha() function

The CSS alpha() function creates a new color by applying a specified alpha value to an existing color.

For example, alpha(from red / 0.5) creates a semi-transparent red color with 50% opacity.

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CSS window-drag property

When used in an installed Progressive Web App (PWA), the window-drag CSS property defines regions of the web app's UI that behave as draggable window title bar areas.

When applied to an element, a click-and-drag pointer interaction moves the top-level application window.

This is useful for PWAs that are installed on desktop operating systems and apps that use the Window Controls Overlay feature to implement custom title bars and draggable areas when the browser-provided title bar is hidden.

The window-drag property standardizes and renames the existing app-region property.

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Media element pseudo-classes

The following CSS pseudo-classes match <audio> and <video> elements based on their state:

  • :playing
  • :paused
  • :seeking
  • :buffering
  • :stalled
  • :muted
  • :volume-locked

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HTML features

The following new HTML features are included in Microsoft Edge.

<camera> and <microphone> elements

The <camera> and <microphone> HTML elements are browser-provided buttons that, upon activation, toggle camera or microphone streams. If required, the button prompts the user to choose whether to grant the page access to the camera and microphone.

The <camera> and <microphone> elements share the same underlying mechanism as the <usermedia> element, with one key distinction: they are designed to request a single capability:

  • The <camera> element specifically requests video capture.
  • The <microphone> element specifically requests audio capture.

Like the <usermedia> element, the <camera> and <microphone> elements embed a browser-controlled, strictly styled UI into the page. This ensures that there's a strong, intentional user signal, before a permission prompt is triggered or a stream is started.

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Reference target

The referenceTarget property of a ShadowRoot object forwards attributes such as for, aria-labelledby, popovertarget, and commandfor to elements inside a shadow DOM. For example, you can use this to link a <label> to its <input>, even if the <input> is in the shadow DOM of a web component.

When a shadow host specifies an element in its shadow tree to act as its reference target, all ID references that point to the shadow host are forwarded to the reference target element instead.

A reference target can also be set in HTML, by using the shadowrootreferencetarget attribute, like in the following example:

<label for="my-checkbox">Checkbox value</label>
<custom-checkbox id="my-checkbox">
  <template shadowrootmode="open" shadowrootreferencetarget="real-checkbox">
    <input id="real-checkbox" type="checkbox">
  </template>
</custom-checkbox>

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autocorrect global html attribute

The autocorrect global HTML attribute controls whether to automatically correct spelling or punctuation errors for user input in <input> and <textarea> elements, and in elements with the contenteditable attribute.

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Web APIs

The following new Web API features are included in Microsoft Edge.

Planned deprecation of the unload event

Edge 152 will introduce the new unload Permission-Policy, to allow creating unload event listeners. The default value is initially allow, but between Edge 152 and Edge 155, the default value will gradually be migrated to deny, such that unload handlers stop firing on pages, unless a page explicitly opts in to re-enable them. To explicitly enable unload event handlers, use the allow value.

  • Edge 152: Unload handlers will stop firing by default for 60% of page loads, unless the site explicitly enables unload handlers via the unload Permission-Policy.
  • Edge 154: Increases to 80% of page loads.
  • Edge 155: Increases to 100% of page loads.

This change is happening in the Chromium project, on which Microsoft Edge is based.

The unload event isn't a dependable way to do the following, because browsers and operating systems can suspend or terminate pages without firing the unload event:

  • Save data.
  • Perform cleanup.
  • Report the end of a session.

Using the unload event can also prevent pages from using the back/forward cache, which might make back and forward navigation slower.

You should migrate to lifecycle events and APIs that are designed for the above scenarios. The long-term direction of the web platform is to remove support for the unload event.

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encryptionScheme attribute for navigator.mediaCapabilities.decodingInfo()

In addition to the contentType and robustness attributes, you can now use the encryptionScheme attribute when querying media capabilities by using navigator.mediaCapabilities.decodingInfo().

This allows you to determine whether a specific combination of codec, robustness, and encryption scheme is supported on the user's device, and therefore detect whether your encrypted media will play.

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CPU Performance API

The CPU Performance API lets you determine the CPU performance of the user's device. You can use this information to provide an improved user experience, possibly in combination with the Compute Pressure API.

The Compute Pressure API provides information about the user device's CPU pressure or utilization and allows applications to react to changes in CPU pressure.

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CSSPseudoElement support for ::backdrop, ::scroll-marker, and ::view-transitions

The CSSPseudoElement interface represents a CSS pseudo-element, and can be obtained by calling Element.pseudo() or CSSPseudoElement.pseudo().

The CSSPseudoElement interface now supports the ::backdrop, ::scroll-marker, and ::view-transitions pseudo-elements, in addition to the ::after, ::before, and ::marker pseudo-elements.

Using the CSSPseudoElement interface with these new pseudo-elements enables you to do the following:

  • ::backdrop: Useful for closing a dialog when the backdrop is clicked, without interfering with clicks inside the dialog's content. This eliminates the need for complex intersection logic to determine where the click occurred.

  • ::scroll-marker: Useful for collecting click statistics.

  • ::view-transitions: Allows you to intercept a view transition mid-flight to start a new view transition, utilizing the coordinates of the currently animating element to avoid sudden visual jumps.

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Connection allowlists

Connection allowlists let you declare and enforce explicit allowlists for network endpoints that can be reached by networking APIs such as the Fetch API. This improves outbound network control, and reduces the risk of unintended connections.

The list of authorized endpoints is distributed from the server through the Connection-Allowlist HTTP response header. Before connecting to a server, the browser evaluates the destination against this allowlist. Connections to verified endpoints are permitted, but destinations that fail to match entries in the allowlist are blocked.

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OpaqueRange for form control text

Use OpaqueRange to represent a live span of text within a form control's value, such as a <textarea> or text-based <input>.

OpaqueRange enables to do the following with ranges of text:

  • Operations such as getBoundingClientRect() and getClientRects().
  • Integration with the CSS Custom Highlight API.

This enables scenarios such as inline suggestions, highlights, and anchored popovers.

OpaqueRange preserves encapsulation by exposing only value offsets, and returns null for startContainer and endContainer.

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WebGPU: subgroup size control

The GPU subgroup-size-control feature allows you to explicitly set the subgroup size in a compute shader.

This is useful when you need to optimize the performance of a compute shader on certain platforms, such as for AI workloads.

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audioSelection:preferred option for getDisplayMedia()

The getDisplayMedia() method now supports the audioSelection:preferred option.

This option allows you to indicate to the browser that you prefer audio sharing along with video.

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Origin trials

The following are origin trials for new experimental APIs that are available in Microsoft Edge.

Origin trials let you try experimental APIs on your own live website for a limited time. To learn more about origin trials, see Use origin trials in Microsoft Edge.

For the full list of available origin trials, see Microsoft Edge Origin Trials.

Name Description Register
Soft navigation heuristics Exposes soft-navigation heuristics for collecting performance metrics in single-page apps. Register
URL and eval hashes in CSP script-src Introduces url- and eval- hashes for script-src CSP directives, replacing hostname-based allowlists and unsafe-eval. Register
<install> HTML element Declaratively install other websites as web apps by using the <install> element. Register
focus-without-user-activation permissions policy Gives an embedder control over programmatic focus from embedded content via the focus-without-user-activation permissions policy. When the policy is denied for a frame, programmatic focus calls (element.focus(), autofocus, window.focus(), dialog.showModal(), and popover focusing) are blocked unless triggered by user activation, or focus is being delegated. Register
Enhanced Canvas TextMetrics Expands the TextMetrics Canvas API, adding selection rectangles, bounding-box queries, and glyph-cluster operations. Register
WebAudio Configurable Render Quantum Lets you specify a custom render quantum size when creating an AudioContext or OfflineAudioContext. Register
Container Timing Monitors when an annotated DOM container is displayed and has finished its initial paint. Register
Separate style and layout durations in the Long Animation Frame API Adds styleDuration, forcedStyleDuration, layoutDuration, and forcedLayoutDuration properties, for deeper CSS performance analysis. Register
Prompt API sampling parameters The topK and temperature sampling parameters let you optimize model behavior per language-model session. Register
Declarative CSS Module Scripts Shares declarative stylesheets with shadow roots, including declarative shadow roots, by using inline style modules. Register
Digital Credentials API - Issuance Support Triggers issuance of user credentials from a credential issuer server to a digital wallet application. Register
prerender_until_script Speculation Rules API action A Speculation Rules API action that prerenders a page, but switches to prefetching when a script executes. Register
HTML in canvas Enables rendering HTML in a canvas by using new drawing methods and the paint event. Register
Gamepad raw input event Instead of relying on frequent polling via navigator.getGamepads(), webpages can listen for gamepadrawinputchanged events. These events are fired whenever changes are detected between input frames from the same device. Register
WebMCP Enables your site to register tools for an in-browser agent to complete tasks on behalf of a user. Register
Autofill Event Detects when browser autofill updates form controls, for adapting custom UI and validation. Register
Email Verification Protocol Enables websites to verify email ownership by using cryptographic tokens that are issued by email providers. This reduces reliance on email one-time passcodes (OTPs), and streamlines sign-up, sign-in, and recovery flows. Register
Prerendering cross-origin iframes Prerenders cross-origin iframes via an opt-in response header, instead of delaying them until page activation. Register
WebAssembly Custom Descriptors V2 Stores data that's associated with source-level types more efficiently, in custom descriptor objects. Register
Speculative Load measurement performance.speculations exposes data about used and unused preloads, prefetches, and prerenders. This helps you measure the effectiveness of speculative loading strategies and optimize performance-versus-cost tradeoffs. Register
Additional WebCrypto algorithms Enables usage of additional WebCrypto algorithms, including a few PQ algorithms. Algorithms enabled: ChaCha20-Poly1305, ML-DSA-44, ML-DSA-65, ML-DSA-87, ML-KEM-768, ML-KEM-1024, MLKEM768-X25519. Register
WebRTC Data Channel: SCTP Negotiation Acceleration Protocol (SNAP) SNAP reduces WebRTC data channel startup latency by embedding SCTP connection setup parameters in the SDP offer/answer exchange. Because WebRTC already uses DTLS to establish a secure channel, the separate SCTP handshake can be avoided, saving up to two network round trips and enabling faster data channel establishment. Register

Note

Portions of this page are modifications based on work created and shared by Chromium.org and used according to terms described in the Creative Commons Attribution 4.0 International License.

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