Google released version 154, the latest stable release of its Chrome web browser, on September 25. The update enables by default a feature that automatically adjusts iframes to match the height of embedded content, as well as a mechanism that prompts users for confirmation before connecting to unencrypted HTTP sites. Numerous CSS and JavaScript API extensions for developers are also included.
The most notable feature in this update is the new iframe size control capability. Previously, when developers wanted an iframe—which embeds a separate HTML document within a web page—to dynamically change height based on content volume, they needed to use JavaScript to measure the embedded document’s dimensions, notify the parent page via postMessage(), and rewrite the height accordingly. In Chrome 154, automatic resizing to match the embedded document’s layout can be achieved simply by specifying CSS on the parent page’s iframe and adding a meta element to the embedded HTML. This significantly simplifies the implementation of elements with variable content volume, such as blog widgets, comment sections, and external widgets.
Scroll marker-related CSS features have also been expanded. The “scroll-marker-group” property, which indicates the current position in horizontally scrolling carousels and similar components, now supports two modes: “links” and “tabs.” In the default “links” mode, the marker group is treated as navigation, allowing focus to move sequentially via the Tab key. When “tabs” is specified, the marker group is interpreted as a tab list, with only the selected marker receiving focus and arrow keys used to move between markers. Content of unselected tabs is excluded from the accessibility tree. Since both visual presentation and WAI-ARIA-compliant semantics can be switched, keyboard operation and screen reader support become easier to implement primarily through CSS.
On the security front, “Ask before HTTP”—which displays a confirmation when connecting to sites beginning with unencrypted “http://”—is now the default setting. While HTTPS encrypts communication between the browser and server, HTTP transmits in plaintext, creating risks of content interception or tampering along the communication path. This change reduces the risk of unintentionally accessing insecure connections. In enterprise environments, the “HttpsOnlyMode” policy can be used to control this behavior.
Developer API expansions also progressed. Various CSS Typed OM constructors are now available from Workers, and the “FontFace.width” property along with the “font-width” descriptor for “@font-face” have been added as aliases for “stretch” and “font-stretch.” The “light dismiss” behavior—where popovers and dialogs close when clicking outside—has been improved so that touch-screen scrolling or right-clicks no longer cause unintended dismissal.
JavaScript gains “Iterator.prototype.includes(),” which checks whether an iterator produces a specified value in a manner similar to “Array.prototype.includes().” The WebSocket constructor now accepts a “WebSocketInit” options object as its second argument, providing a format ready for future extensions. Additionally, a “targetAddressSpace” option allows specifying the connection target as either “local” or “loopback” address space, useful for connecting to local servers that don’t support HTTPS.
The Background Fetch API now enforces CORS, and access to local or loopback addresses requires Local Network Access permission. In Secure Payment Confirmation, a “NotSupportedError” is now returned when the specified language tag does not match the language of the payment confirmation dialog. For Isolated Web Apps registered on ChromeOS’s allowlist, a “Window Shape API” has been added, enabling the definition of non-rectangular window shapes or windows with multiple separated regions—useful for creating widgets and floating panels.
It should be noted that while the release notes mention support for the CSS “text-decoration-inset” property, according to ChromeStatus the actual release has been postponed to Chrome 156.
In origin trials, testing of “Private Verification Tokens (PVT)” has begun. This mechanism allows trust information established by users during normal browsing to be carried into incognito windows in a privacy-conscious manner, with the intended use case of reducing the frequency of additional authentication such as CAPTCHAs during private browsing.
The next stable release, Chrome 155, is scheduled for October 6, 2026 local time.
Meanwhile, Google is also improving Chrome’s cross-device functionality. According to U.S. media outlet The Verge, the existing feature for sending tabs between mobile and desktop now includes scroll position memory. Even when reading lengthy research materials, users no longer need to manually locate where they left off when switching devices. Form content entered but not yet submitted is also preserved, allowing users to continue tedious tasks started on mobile on a desktop, or switch to mobile while away from home to complete them.
The Gemini AI assistant integrated into Chrome has also gained study support features. The ability to analyze, visualize, and summarize documents, web pages, and YouTube videos now supports more media formats, including podcasts and videos hosted outside of YouTube. After playing audio or video files, users can ask Gemini to identify key points, search for specific information, or explain confusing sections. Additionally, a feature that generates interactive quizzes based on content displayed in open tabs has been added. This quiz feature is currently rolling out in English for desktop users in the United States and India, with plans to expand to other regions and mobile devices in the coming months.