Microsoft shipped Edge 154 on September 24, 2026, a release that lands squarely on front-end developers’ desks. The most visible change touches scroll-marker-group, which gains a second mode modeled on the tablist pattern. The browser also locks the Background Fetch API behind the same CORS and Local Network Access rules as regular Fetch, and formalizes a faster ship cadence: every two weeks.
Two modes for scroll-marker-group
The scroll-marker-group CSS property previously supported a single behavior, close to a navigation list. Edge 154 introduces the tabs mode, which replicates a tablist’s accessibility pattern: the ::scroll-marker-group container gets the tablist role, each ::scroll-marker becomes a tab, and the associated source element takes the tabpanel role. Pressing Tab from an active marker moves focus straight into the matching panel, and content from inactive tabs is hidden from the accessibility tree. The default links mode is unchanged and still mimics a classic <nav><a> structure.
This distinction removes the need to hand-roll ARIA for a scroll-driven carousel or tabbed interface, a common requirement on product pages and portfolios built with native CSS-driven design.
Background Fetch aligned with Fetch’s rules
The Background Fetch API now enforces the same CORS checks as the standard Fetch API, along with Local Network Access restrictions when a request targets a local or loopback server. Previously, a site could sidestep these checks by using Background Fetch instead of a regular Fetch call; Edge 154 closes that gap.
Other changes worth tracking
| Change | Area | Practical effect |
|---|---|---|
| WebSocket options argument | Web API | Subprotocols can now be passed via an options object, alongside the existing string form |
| targetAddressSpace | Web API | Declares that a WebSocket connection to a public host actually targets a local server |
| text-decoration-inset | CSS | Controls the gap between text and its decorations (underline, line-through) |
| frame-sizing | HTML/CSS | Automatically sizes an iframe to match its content |
| Iterator.prototype.includes() | JavaScript | Tests whether an iterator yields a value, without converting it to an array first |
The new options argument on the WebSocket constructor sums up the spirit of this release: bringing a long-standing API in line with more recent language conventions.
// Before: only a subprotocol string was accepted
const legacy = new WebSocket("wss://example.com:8080", "soap");
// Edge 154: an options object is now accepted too
const socket = new WebSocket("wss://example.com:8080", {
protocols: "soap",
targetAddressSpace: "local"
});A two-week release cycle
Edge is moving to a two-week release cadence, down from four. Paired with build tools that are already tightening their own release cycles, this shift shortens the gap between a feature landing in Chromium and reaching stable Edge, but it also demands more frequent compatibility tracking.
A two-week cycle turns browser compatibility into an ongoing tracking task, not a one-time check before shipping.
The tabs mode of scroll-marker-group remains a recent Chromium-only addition: before shipping it to production, check an up-to-date compatibility table for actual Firefox and Safari support, or keyboard navigation may degrade on browsers that have not implemented it yet.
Key takeaways
Edge 154 does not reshape the web platform, but it advances work already underway: accessibility for scroll-driven interfaces, consistent CORS rules across fetch-style APIs, and modernization of long-standing APIs like WebSocket. The move to a two-week cycle deserves particular attention from teams testing sites on the beta and dev channels.
The tabs mode for scroll-marker-group fixes a real accessibility gap that many scroll-driven interfaces have been carrying for years without a clean native solution. The open question is how long Firefox and Safari take to catch up, as is often the case with recent CSS pseudo-elements — a lag that has already caused trouble with other features shipped to production too early. — Simon Janvier
Further reading
Primary source: Microsoft Edge 154 web platform release notes, Microsoft Learn.
