New Web Platform Features in October 2025: Stable and Beta Browser Updates

Stay informed about the latest advancements on the web platform with our monthly update. This post highlights interesting new features that have landed in stable and beta web browsers throughout October 2025, helping you save and categorize content based on your preferences.

Stable Browser Releases

October 2025 saw the stable releases of Chrome 142 and Firefox 144. Let's delve into what these updates bring to the web platform.

Note: Browser compatibility data pulled from MDN is included in these posts and may not have been updated yet for very recent browser releases. This post will show the correct information as soon as it appears in the browser-compat-data release.

The View Transitions API for Single-Page Apps

Firefox 144 introduces support for same-document view transitions. This includes support for:

• The :active-view-transition pseudo-class
• The view-transition-class property
• The view-transition-name property
• The ::view-transition pseudo-element
• The ::view-transition-group() pseudo-element
• The ::view-transition-image-pair() pseudo-element
• The ::view-transition-new() pseudo-element
• The ::view-transition-old() pseudo-element

This makes same-document view transitions Baseline Newly available.

Browser Support Chrome: 125, Edge: 125, Firefox: 144, Safari: 18

The command and commandfor attributes on the <button> element

Firefox 144 now supports the command and commandfor attributes. You can find out more about these attributes in Introducing command and commandfor.

Browser Support Chrome: 135, Edge: 135, Firefox: 144

The moveBefore() method

The moveBefore() method is now supported by Firefox on the Element, DocumentFragment, and Document interfaces. This allows you to move an immediate child element of an object before another of its child elements, with both elements retaining their state.

Learn more in Preserve state during DOM mutations with moveBefore().

:target-before and :target-after pseudo-classes

Chrome 142 adds pseudo-classes that match scroll markers located before or after the active marker (matching :target-current) within the same scroll marker group, as determined by flat tree order:

• target-before: Matches all scroll markers that precede the active marker in the flat tree order within the group.
• target-after: Matches all scroll markers that follow the active marker in the flat tree order within the group.

Browser Support Chrome: 135, Edge: 135, Firefox: x, Safari: x

Range syntax for style container queries and if()

Chrome 142 enhances CSS style queries and the if() function by adding support for range syntax.

This extends style queries beyond exact value matching (e.g., style(--theme: dark)). Developers can now use comparison operators (such as > and <) to compare custom properties, literal values (e.g., 10px or 25%), and values from substitution functions like attr() and env(). For a valid comparison, both sides must resolve to the same data type. This feature is limited to the following numeric types: <length>, <number>, <percentage>, <angle>, <time>, <frequency>, and <resolution>.

Interest Invokers (the interestfor attribute)

Chrome 142 also adds an interestfor attribute to <button> and <a> elements. This attribute enables "interest" behaviors for the element. When a user "shows interest" in the element, actions are triggered on the target element, for example, showing a popover.

The user agent detects when a user shows interest in the element through methods such as holding the pointer over the element, hitting special hotkeys on the keyboard, or long-pressing the element on touchscreens. When interest is shown or lost, an InterestEvent fires on the target, which has default actions for popovers, such as showing and hiding the popover.

Beta Browser Releases

Beta browser versions offer a sneak peek into features expected in upcoming stable releases. This is an excellent opportunity to test new functionalities or removals that might affect your site before a wider rollout. This month's new betas include Firefox 145 and Chrome 143, with Safari 26.1 continuing its beta phase.

• Firefox 145 includes the source property of the ToggleEvent interface and the Atomics.waitAsync() static method.
• Chrome 143 introduces CSS anchored fallback container queries. This features @container anchored(fallback) to style descendants of anchor-positioned elements based on which position-try-fallbacks value is applied.