New to the web platform in October

Discover some of the interesting features that have landed in stable and beta web browsers during October 2025.

Rachel Andrew

Published: October 30, 2025

Stable browser releases

Chrome 142 and Firefox 144 released to stable during October, this post takes a look at what that means for the web platform.

The View Transitions API for Single-Page Apps

Firefox 144 includes 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.

The command and commandfor attributes on the <button> element

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

The moveBefore() method

The moveBefore() method is now supported by Firefox on the Element, DocumentFragment and Document interfaces. This lets you move an immediate child element of the 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 that are 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.

Range syntax for style container queries and if()

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

It extends style queries beyond exact value matching (for example, style(--theme: dark)). Developers can use comparison operators (such as > and <) to compare custom properties, literal values (for example, 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. It 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 adds "interest" behaviors to 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 give you a preview of things that will be in the next stable version of the browser. It's a great time to test new features, or removals, that could impact your site before the world gets that release. New betas this month are Firefox 145 and Chrome 143, with Safari 26.1 ongoing.

Firefox 145 includes the source property of the ToggleEvent interface and the Atomics.waitAsync() static method.

Chrome 145 includes CSS anchored fallback container queries. This introduces @container anchored(fallback) to style descendants of anchor-positioned elements based on which position-try-fallbacks value is applied.