Apple Ships Safari Technology Preview 242 with Major CSS and Accessibility Fixes

Breaking: Safari Technology Preview 242 Now Available

Apple has released Safari Technology Preview 242, the latest experimental build of its web browser, with critical fixes and new features for CSS, accessibility, and HTML parsing. The update is available immediately for macOS Tahoe and macOS Sequoia.

Apple Ships Safari Technology Preview 242 with Major CSS and Accessibility Fixes — Source: webkit.org

“This release brings significant enhancements to web standards compatibility, particularly for developers using advanced CSS and making sites more accessible,” said a WebKit spokesperson.

Accessibility Overhaul

Accessibility receives a major boost. VoiceOver will no longer incorrectly read decorative images with role="presentation", improving screen reader accuracy.

Support for customizable <select> elements with appearance: base-select on macOS has been fixed, ensuring native-like behavior for assistive technologies.

CSS: New Attributes and Font Control

CSS developers gain support for the attr() function from CSS Values Level 5, enabling dynamic property values. Additionally, the oblique-only value for font-synthesis-style is now available, giving finer control over font styling.

Several bugs were squashed. The @media (prefers-color-scheme: dark) query now works inside iframes with color-scheme: dark. The position-try-order property correctly uses the containing block’s writing mode.

Percent-height replaced elements in shrink-to-fit containers no longer compute stale widths. Table cell nowrap minimum width quirks are now limited to quirks mode.

Checkbox outlines are aligned properly. Anchor-positioned elements anchored to children of sticky boxes now stick correctly. Pseudo-elements sort correctly in anchor tree order.

A layout bug with ligatures and font-size: 0 is fixed. The :in-range and :out-of-range pseudo-classes update when readonly changes. View-timeline-inset serialization now coalesces identical values.

Forms Fix: Select Multiple Behavior

Forms see one fix: <select multiple> now correctly fires onchange when the mouse button is released far outside the element.

HTML: Dialog Closedby and Parser Optimizations

HTML adds the closedby attribute on <dialog> elements, giving developers more control over dialog dismissal.

The HTML parser fast path gets multiple fixes: correctly processes escaped attribute values longer than one character, detects nested <li> elements, and uses adjusted current node for MathML/SVG integration points.

Image Handling

Images with srcset attribute insertion issues have been resolved, improving responsive image loading.

Background

Safari Technology Preview is Apple’s experimental browser for developers to test upcoming WebKit features before they ship in Safari. It runs alongside the standard Safari and requires macOS Tahoe or Sequoia.

Existing users can update via System Settings → General → Software Update. The release includes changes between WebKit revisions 310187@main and 310599@main.

What This Means

For web developers, this update provides a stable testing ground for cutting-edge CSS and HTML features. The accessibility fixes ensure better screen reader compatibility, which is critical for inclusive design.

The CSS attr() function and oblique-only font support give more creative control. The numerous bug fixes improve rendering accuracy across layouts and forms.

Users with assistive technologies will benefit from more reliable VoiceOver behavior and form interactions. Overall, this release moves Safari closer to full compliance with modern web standards.