Safari 26.3 Brings Welcome Improvements for Users and Developers – 9to5Mac

Along with today’s system updates, Apple released Safari 26.3 with a mix of under-the-hood improvements and at least one major usability improvement for Vision Pro users. Here are the details.

Better full screen control in visionOS, improving efficiency for everyone

With Safari 26.3, Vision Pro users on visionOS 26.3 will see Safari automatically mute their surroundings when the video goes full-screen, a change Apple says helps “focus on the content.”

In addition, Safari 26.3 introduces support for Zstandard (Zstd), an open real-time compression algorithm developed by Meta that essentially compresses textual web assets before they are delivered to browsers and then quickly decompresses them on the device.

Apple says that “Zstandard decompresses quickly, which reduces the load on users’ devices. It also compresses fast enough to do this at runtime, while Brotli is usually precompressed during the build process.”

Apple notes that for Zstd support to work, users must be running Safari 26.3 on iOS 26.3, iPadOS 26.3, visionOS 26.3, and macOS Tahoe 26.3.

If you are a developer, you may be pleased to know that the Safati 26.3 Navigation API now “exposes AbortSignal we NavigateEvent which is triggered when navigation is interrupted, which Apple says is a “reliable way to cancel work in progress when navigation is interrupted.”

Finally, WebKit for Safari 26.3 includes the following bug fixes and improvements for developers:

CSS

• Fixed a style resolution loop that occurred when a position-try the box was inside and display: none ancestor. (163691885)
• Fixed an issue where elements placed by an anchor would repeatedly transition display: block on display: none cause position jumps during animation. (163862003)
• Fixed where issue fixed-placed boxes using position-area were incorrectly included in the calculation of the block containing the scroll. (164017310)
• Fixed where issue text-decoration: underline was rendered too high when text-box-trim was applied to the root inline box. (165945326)
• Fixed an issue with multi-column layouts when widows and text-indent properties will cause the part of the paragraph that moves to the next column to be indented incorrectly. (165945497)
• Fixed an issue with CSS cursors being liked move, all-scroll, ew-resizeand ns-resize was not displaying correctly. (166731882)

HOUSE

• Fixed incorrect timestamp handling and switched to use raw touch timestamp. (164262652)

Media

• Fixed an issue where the full screen button in video controls in visionOS does not visually indicate interactivity by extending the glow effect to all button.circular elements. (164259201)
• Fixed video viewer mode for iframe videos on macOS. (164484608)
• Fixed an issue where Safari could not play live videos when sourceBuffer the content is removed and added again, causing the search to not complete. (165628836)

Rendering

• Fixed a placement or transformation issue elements containing HDR JPEGs with gain maps would render incorrectly as SDR. (163517157)

Safe Browsing

• Fixed a bug where if Safe Browsing requested an entry in the public suffix list and the Safe Browsing vendor responded that the entire effective TLD was unsafe, the entire site would be flagged as unsafe. (168155375)

To learn more about Safari 26.3, click this link.

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