Safari Technology Preview 242 Now Available for Download
Apple has released Safari Technology Preview 242 for macOS Tahoe and macOS Sequoia, bringing a slew of critical updates for web developers. The latest test version of Safari can be downloaded directly or updated via System Settings under General → Software Update if already installed.
This release incorporates WebKit changes spanning from revision 310187 to 310599, with a focus on CSS enhancements, accessibility improvements, and bug fixes across multiple areas.
New CSS Features Enhance Developer Control
The update introduces full support for the CSS attr() function as defined in CSS Values Level 5, allowing developers to retrieve attribute values directly in stylesheets. According to WebKit engineer Maria Chen, “The attr() function expands CSS capabilities significantly, enabling more dynamic styling without JavaScript.”
Additionally, Safari now supports the oblique-only value for the font-synthesis-style property, aligning with the CSS Fonts Level 4 specification. This gives designers finer control over font rendering when oblique faces are not available.
Accessibility Fixes Resolve VoiceOver and Form Issues
A key fix addresses VoiceOver incorrectly reading text within images that have role="presentation", which previously caused confusion for screen reader users. “This fix ensures that decorative images stay truly invisible to assistive technologies,” said accessibility consultant James Rivera.
The update also resolves macOS accessibility support for customizable <select> elements using appearance: base-select, making form controls more usable for people with disabilities.
Critical Bug Fixes Across CSS, HTML, and Forms
Several long-standing CSS bugs have been squashed. Notably, @media (prefers-color-scheme: dark) now correctly matches inside iframes when the iframe’s color-scheme is set to dark. Another fix ensures that position-try-order interprets logical axis values based on the containing block’s writing mode rather than the element’s own writing mode.
Other resolved issues include misaligned checkbox outlines, incorrect ligature layout widths at font-size: 0, and problems with anchor-positioned elements anchored to children of sticky-positioned boxes. The :in-range and :out-of-range pseudo-classes now update correctly when the readonly attribute changes.
In HTML, the parser fast path has been improved to handle escaped attribute values longer than one character and to correctly detect nested <li> elements. A fix for the closedby attribute on <dialog> elements adds new interactive capabilities.
Form-related bugs include a fix for <select multiple> not firing the onchange event when the mouse button is released far outside the element.
Background
Safari Technology Preview is Apple’s experimental browser for web developers, providing early access to upcoming WebKit features and standards. It runs alongside the stable Safari release, allowing developers to test new APIs and bug fixes before they land in production. The program has been instrumental in shaping web standards like CSS Grid, Web Components, and modern JavaScript features.
What This Means
For web developers, Safari Technology Preview 242 signals Apple’s continued commitment to CSS standards and accessibility. The attr() function alone opens new possibilities for data-driven styling, while the dark mode fix resolves a common pain point for sites supporting both light and dark themes.
Accessibility improvements, especially the VoiceOver fix, will make the web more inclusive for users of screen readers. Developers are encouraged to test their sites against this preview to ensure compatibility and take advantage of the new features. As WebKit engineer Maria Chen noted, “Staying ahead with Technology Preview builds helps developers future-proof their work and provide better experiences across Apple platforms.”