Safari Technology Preview 242: Key Enhancements and Fixes Explained

Welcome to the latest update of Safari Technology Preview, version 242. This release brings a host of improvements and bug fixes to WebKit, enhancing accessibility, CSS functionality, form handling, and HTML parsing. Below, we answer common questions about what this update includes, how to get it, and what developers and users need to know.

1. How can I get Safari Technology Preview 242 and what are the system requirements?

This release is available for macOS Tahoe and macOS Sequoia. If you already have Safari Technology Preview installed, simply open System Settings → General → Software Update to upgrade. For new installations, download it from the official Apple Developer website. The update includes WebKit changes between revisions 310187 and 310599, bringing a range of fixes and features across multiple areas.

Safari Technology Preview 242: Key Enhancements and Fixes Explained — Source: webkit.org

2. What accessibility improvements were made in this version?

Two key accessibility issues were resolved. First, VoiceOver will no longer read text inside images that have role="presentation", preventing redundant announcements. Second, macOS accessibility support was improved for customizable <select> elements using appearance: base-select, ensuring screen readers interact correctly with these custom dropdowns. These changes enhance the browsing experience for users relying on assistive technologies.

3. What new CSS capabilities were introduced?

This release adds support for the CSS attr() function from CSS Values Level 5, allowing authors to retrieve attribute values directly within CSS. Additionally, the oblique-only value for font-synthesis-style is now supported, as defined in CSS Fonts Level 4. This enables more precise control over font style synthesis, particularly when only oblique (slanted) styles are needed without italic alternatives.

4. Which CSS bugs were fixed in this update?

Several issues were addressed. For instance, @media (prefers-color-scheme: dark) inside an iframe now works correctly even when the iframe’s color-scheme is set to dark. The position-try-order property now uses the containing block’s writing mode for logical axis values, fixing layout inconsistencies. Percent-height replaced elements no longer compute stale preferred widths in shrink-to-fit containers. Additionally, checkbox outlines are now properly aligned, anchor-positioned elements stick correctly with sticky parents, and ligatures at font-size: 0 no longer cause non-zero layout widths. The :in-range and :out-of-range pseudo-classes also update properly when the readonly attribute changes.

5. What HTML and Forms enhancements are included?

On the HTML side, support was added for the closedby attribute on <dialog> elements, giving developers more control over dialog dismissal. The HTML parser fast path was improved to correctly handle escaped attribute values longer than one character, properly detect nested <li> elements, and use the adjusted current node for MathML and SVG integration point checks. In Forms, a fix ensures that <select multiple> now fires the onchange event when the mouse button is released far outside the element, making multi-select behavior more reliable.

6. Were there any changes related to images?

While the release notes mention a fix for inserting images with a srcset attribute, details were cut off; however, it indicates continued attention to image rendering performance and correctness. This is part of ongoing efforts to refine how Safari handles responsive images. For full details, refer to the official WebKit changelog.

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