Safari Technology Preview 241: Key Updates and Fixes

Overview of Safari Technology Preview 241

Apple has released Safari Technology Preview 241, the latest experimental version of its web browser, now available for download on macOS Tahoe and macOS Sequoia. This release continues the tradition of providing developers and early adopters with a glimpse into upcoming WebKit improvements. If you already have a previous version installed, you can update easily via System Settings under General → Software Update.

Safari Technology Preview 241: Key Updates and Fixes — Source: webkit.org

This update incorporates WebKit changes from revisions 309287@main to 310186@main, addressing a range of bugs and introducing new features. Below, we break down the most notable enhancements and fixes across accessibility, animations, and CSS.

Accessibility Enhancements

Accessibility remains a cornerstone of WebKit development, and this release tackles several issues that improve assistive technology compatibility and user experience.

Resolved Accessibility Issues

Speech Synthesis Queue Management: Previously, calling speechSynthesis.cancel() would erroneously remove utterances added by later speechSynthesis.speak() calls. This has been fixed, ensuring queued speech is properly managed. (309349@main)
MathML Table Row and Cell Bounding Boxes: Incorrect bounding boxes for MathML table rows and cells could cause layout and interaction problems. The fix ensures accurate dimensions for these elements. (309640@main)
Combobox Focus Forwarding: Comboboxes now correctly forward focus to their aria-activedescendant, allowing assistive technologies to interact with list items as intended. (309641@main)
Aria-Owns for Accessible Names: The aria-owns attribute is now properly respected when computing accessible names from element content, improving screen reader accuracy. (310020@main)

Animation Improvements

Animations are critical for modern web experiences, and this update fixes a key issue related to viewport-dependent units.

Resolved Animation Issue

Animation Fill Mode with Viewport Units: When the viewport is resized, animation-fill-mode now correctly applies viewport-based units, ensuring consistent animation behavior across different screen sizes. (310007@main)

CSS Enhancements and Fixes

The CSS updates in Safari Technology Preview 241 are substantial, introducing new features and resolving numerous bugs that affect layout, rendering, and performance.

New CSS Features

Stretch Keyword for Box Sizing: Support for the stretch keyword in box-sizing properties has been added, giving developers more flexibility in sizing elements. (309405@main)
CSS Scroll Anchoring: Stable support for CSS scroll anchoring is now available, preventing unwanted page jumps when content loads above the user’s scroll position. (310113@main)

Resolved CSS Issues

Line Separator Rendering: The character U+2028 LINE SEPARATOR is now rendered as a forced line break per the CSS specification, aligning with web standards. (309701@main)
Outline Offset for Auto Outlines: Fixed an issue on macOS where outline-offset was incorrectly inflated when using outline: auto. (309812@main)
Font Family Serialization: Quotes around family names that match CSS-wide keywords or generic families are now preserved during serialization, preventing unexpected font fallbacks. (309959@main)
Unnecessary Font Downloads: Previously, a font could be downloaded even if no character in the document matched its unicode-range. This wasteful behavior has been corrected. (309360@main)
Flex Item with Percentage-Height Image: A flex item containing an image with a percentage height now shrinks correctly around the image, improving layout stability. (309544@main)
View Transition Snapshot Color Space: View Transition snapshots were incorrectly stored in sRGB, causing rendering issues with non-sRGB colors. They are now stored correctly. (310012@main)
Performance with Contain: Layout: The use of contain: layout previously caused significantly slower forced layouts when all siblings created their own formatting context. This performance bottleneck has been resolved. (310173@main)
Underline Splitting with Ruby Text: Underlines no longer split when a ruby base expands due to long ruby text, ensuring consistent text decoration. (309356@main)
Color Scheme Repainting for Composited Iframes: Changing color-scheme now correctly repaints the background of composited iframes, eliminating stale visuals. (309567@main)
Popover Nested Children with Absolute Positioning: Nested children of a popover element using position: absolute previously failed to render; this has been fixed. (310019@main)
Color: Initial in Dark Mode: The color: initial property now resolves to the correct color in dark appearance mode, avoiding unexpected hues. (309430@main)
Anchor Scope with Display: Contents: An element with display: contents now correctly establishes an anchor scope when using anchor-scope. (309946@main)
Media Query Resolution Regression: A regression where media queries could fail to resolve correctly has been fixed, restoring reliable responsive design behavior. (This fix is part of the latest changes.)

Conclusion

Safari Technology Preview 241 brings a robust set of improvements that refine core web technologies. Developers working on accessibility, animations, and CSS will find these updates particularly valuable for building more reliable and performant websites. As always, feedback from the developer community helps shape future releases, so be sure to test your projects and report any issues.

To download or update, visit Apple’s Safari Technology Preview page.