New to the web platform in April

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

Rachel Andrew

Published: April 30, 2025

Stable browser releases

In April 2025 Firefox 137, Firefox 138, Chrome 135, and Chrome 136 became stable. This post looks at the new features added to the web platform during a month that saw two releases from Chrome and Firefox.

Carousels land in Chrome

Several of the features that made their way into Chrome in version 135 enable the creation of carousels and other paged experiences on the web.

The ::scroll-button() and ::scroll-marker() pseudo-elements let you add buttons and markers to any scrollable area on your site, giving it navigation controls and a way to show the user where they are as they progress through the carousel.

Browser Support

  • Chrome: 135.
  • Edge: 135.
  • Firefox: not supported.
  • Safari: not supported.

Source

The ::column pseudo-element that lets you style a column fragment.

Browser Support

  • Chrome: 135.
  • Edge: 135.
  • Firefox: not supported.
  • Safari: not supported.

Source

The interactivity property specifies whether an element and its flat tree descendants (including text runs) are inert or not.

Browser Support

  • Chrome: 135.
  • Edge: 135.
  • Firefox: not supported.
  • Safari: not supported.

Making an element inert affects whether it can be focused, edited, selected, and searchable by find-in-page. It also affects whether it is visible in the accessibility tree.

You can learn more in Carousels with CSS.

The command and commandfor attributes

Also in Chrome 135 are the command and commandfor attributes. These enhance and replace the popovertargetaction and popovertarget attributes. These new attributes can be added to buttons, letting the browser address some core issues around simplicity and accessibility, and provide built-in common functionality.

Find out more in Introducing command and commandfor.

Browser Support

  • Chrome: 135.
  • Edge: 135.
  • Firefox: behind a flag.
  • Safari Technology Preview: supported.

Source

The CSS shape() function

The shape() CSS function in Chrome 135 is used to define a shape for the clip-path and offset-path properties. Learn how to use it for responsive clipping. This function was shipped in Safari 18.4 and is also in Firefox Nightly, hopefully it will be Baseline Newly available very soon.

Browser Support

  • Chrome: 135.
  • Edge: 135.
  • Firefox Technology Preview: supported.
  • Safari: 18.4.

Source

Atomics.pause()

Firefox 137 includes Atomics.pause() making this feature Baseline Newly available. This static method provides a micro-wait primitive that hints to the CPU that the caller is spinning while waiting on access to a shared resource. This lets the system reduce the resources allocated to the core (such as power) or thread, without yielding the current thread.

Browser Support

  • Chrome: 133.
  • Edge: 133.
  • Firefox: 137.
  • Safari: 18.4.

Source

CSS hyphenate-limit-chars

Firefox 137 also includes the CSS hyphenate-limit-chars property. This property specifies a minimum word length to allow hyphenation of words, and a minimum number of characters before and after the hyphen.

Browser Support

  • Chrome: 109.
  • Edge: 109.
  • Firefox: 137.
  • Safari: not supported.

Source

RegExp.escape

The RegExp.escape static method has landed across all browsers within a few months, and becomes Baseline Newly available as it lands in Chrome 136.

This method escapes any potential regular expression syntax characters in a string, returning a new string that can be safely used as a literal pattern for the RegExp() constructor.

Browser Support

  • Chrome: 136.
  • Edge: 136.
  • Firefox: 134.
  • Safari: 18.2.

Source

Error.isError()

The Error.isError() static method determines whether the passed value is an Error. It's included in Firefox 138. While it does have browser support in all browsers, it's not quite yet considered Baseline Newly available as Safari currently returns false for DOMException instances.

Browser Support

  • Chrome: 134.
  • Edge: 134.
  • Firefox: 138.
  • Safari: 18.4.

Source

The Login Status API for FedCM

Firefox 138 supports the Login Status API when using the Federated Credential Management (FedCM) API. This is used to set and check whether a browser user is logged in to an identity provider. Firefox 138 includes support for the NavigatorLogin interface, the navigator.login property, and the Set-Login HTTP response header.

Browser Support

  • Chrome: 120.
  • Edge: 120.
  • Firefox: 138.
  • Safari: not supported.

Source

Importmap integrity

In Firefox 138 the importmap value of the type attribute of the <script> element now supports the integrity key. This allows the ES module URLs referenced in the import maps to be matched against their integrity metadata. This feature is now Baseline Newly available.

Browser Support

  • Chrome: 45.
  • Edge: 17.
  • Firefox: 43.
  • Safari: 11.1.

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 are Firefox 139 and Safari 18.5.

The Safari 18.5 beta so far includes just a few bug fixes after their large 18.4 release.

As of the time of writing Firefox haven't published their release notes, however the beta seems to include shipping of the Temporal API, making Firefox the first browser to ship this improved version of Date. Also implementation of <dialog> request.close(), which will bring this method to Baseline Newly available.