December’s browser updates: what’s new

The final stable releases of 2022 arrived in December, with Firefox 108 and Safari 16.2 becoming generally available. Here’s a rundown of the web platform features that shipped or entered beta during the month.

Stable releases

Image dimensions on <source>

Firefox 108 adds support for the height and width attributes on the <source> element when used inside a <picture> element. The attributes take an integer representing the image’s dimension in pixels, without a unit.

Trigonometric CSS functions

Firefox now supports the CSS trigonometric functions: sin(), cos(), tan(), asin(), acos(), atan() and atan2().

Last baseline alignment, cross-engine

Safari 16.2 brings support for last baseline alignment in CSS grid and flexbox layout. With this addition, the feature is now available in all three major browser engines.

More font variant options in Safari

Safari 16.2 also expands the values accepted by the font-variant-alternates CSS property: annotation(value-name), character-variant(value-name), ornaments(value-name), styleset(value-name), stylistic(value-name) and swash(value-name). The associated @font-feature-values at-rule is supported as well.

Beta releases

December’s beta channel includes Firefox 109, Safari 16.3 and Chrome 109, giving developers a preview of what’s coming next.

Safari 16.3’s only listed new feature is the Content-Security-Policy prefetch-src directive, alongside a set of fixes.

Chrome 109 supports MathML Core, the language for embedding mathematical notation in HTML and SVG.

On Chrome for Android, two notable additions arrived. Secure Payment Confirmation (SPC) is a proposed web standard that lets customers authenticate with their payment provider using a platform authenticator, typically a fingerprint sensor or other device screen-unlock method. The Origin Private File System (OPFS), part of the File System Access API, is also now available on Android—with the exception of the show{OpenFile, SaveFile, Directory}Picker() methods and Drag and Drop API integration.

For CSS, Chrome 109 introduces the lh length unit, which equals the computed line-height value of the element it’s applied to. The beta also includes the hyphenate-limit-chars property, which sets the minimum number of characters in a hyphenated word.

Firefox 109’s release notes had not been updated at the time of writing.

Wrapping up the year

This post is the 12th edition of the monthly “New to the web” series for 2022. Many of this year’s features and CSS fixes were part of the Interop 2022 cross-browser effort; the Chrome team has published an end-of-year report on that initiative’s outcomes. For those tracking compatibility data, MDN also released an updated list of browser compatibility changes.