Safari Technology Preview Release 242 is now available for download for macOS Tahoe and macOS Sequoia. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update.

This release includes WebKit changes between: 310187@main…310599@main.

Accessibility

Resolved Issues

• Fixed an issue where VoiceOver read text within images that have role="presentation". (310483@main) (159304061)
• Fixed macOS accessibility support for customizable <select> elements using appearance: base-select. (310441@main) (173696010)

CSS

New Features

• Added support for the CSS attr() function from CSS Values Level 5. (310246@main) (173700363)
• Added support for the oblique-only value for font-synthesis-style as defined in CSS Fonts Level 4. (310409@main) (173730766)

Resolved Issues

• Fixed an issue where @media (prefers-color-scheme: dark) inside an iframe did not match when the iframe’s color-scheme was set to dark. (310465@main) (142072593)
• Fixed position-try-order to interpret logical axis values using the containing block’s writing mode instead of the element’s own writing mode. (310277@main) (169501069)
• Fixed an issue where percent-height replaced elements computed stale preferred widths in shrink-to-fit containers. (310194@main) (171184282)
• Fixed an issue where the table cell nowrap minimum width calculation quirk was applied outside of quirks mode. (310195@main) (171410252)
• Fixed an issue where checkbox outlines appeared misaligned. (310323@main) (172742551)
• Fixed an issue where anchor-positioned elements anchored to children of sticky-positioned boxes did not stick correctly. (310255@main) (172884148)
• Fixed an issue where pseudo-elements were not sorted correctly when sorting anchor elements by tree order. (310407@main) (173032203)
• Fixed an issue where ligatures caused a non-zero layout width for text with font-size: 0. (310394@main) (173840866)
• Fixed :in-range and :out-of-range pseudo-classes to correctly update when the readonly attribute changes. (310484@main) (173978657)
• Fixed an issue where view-timeline-inset serialization failed to coalesce identical values. (310590@main) (174096313)

Forms

Resolved Issues

• Fixed an issue where <select multiple> did not always fire onchange when the mouse button was released far outside the element. (310482@main) (173882861)

HTML

New Features

• Added support for the closedby attribute on <dialog> elements. (310487@main) (173974767)

Resolved Issues

• Fixed the HTML parser fast path to correctly process escaped attribute values longer than one character. (310209@main) (173673581)
• Fixed the HTML parser fast path to correctly detect nested <li> elements. (310492@main) (173983892)
• Fixed the HTML parser fast path to use the adjusted current node for MathML and SVG integration point checks. (310593@main) (174096305)

Images

Resolved Issues

• Fixed an issue where inserting an image with a srcset attribute into a dynamically created iframe resulted in an invisible image. (310446@main) (66849050)

JavaScript

Resolved Issues

• Fixed an issue where class instance field initializers did not have the correct evaluation context when used inside arrow functions and nested scopes. (310594@main) (173296563)
• Fixed %ArrayIteratorPrototype%.next() to return { done: true } instead of throwing a TypeError when the source TypedArray is detached and the iterator has already completed. (310292@main) (173759106)
• Fixed an issue where a fixed-count mixed-width character class in a regular expression did not correctly restore the index on backtrack. (310477@main) (173972458)

Media

Resolved Issues

• Fixed an issue where scrubbing a video in full-screen mode could cause it to exit full-screen. (310415@main) (172682230)
• Fixed an issue where HTMLMediaElement.preservesPitch = true did not work when the element was connected to an AudioContext. (310521@main) (173727365)

Networking

New Features

• Added support for secure cookies on loopback hosts. (310542@main) (137604100)

Rendering

Resolved Issues

• Fixed a regression where nested column flexboxes could cause content to render at the wrong size. (310253@main) (173321492)
• Fixed a regression where nested empty inline boxes accumulated an incorrect vertical offset, causing inline elements to stack as block-level elements. (310313@main) (173723162)
• Fixed an issue where pseudo-elements were incorrectly included in outline rect collection. (310531@main) (174033087)

SVG

New Features

• Added support for the lang and xml:lang attribute in SVG. (310495@main) (143751056)

Resolved Issues

• Fixed an issue where SMIL animations of href or xlink:href on SVG <image> elements had no visual effect. (310236@main) (96316808)
• Fixed an issue where SVG gradient animations did not work unless y1 and y2 attributes were explicitly specified. (310257@main) (123457088)
• Fixed an SVG <tspan> positioning bug with xml:space="preserve" that caused multi-line text to render incorrectly. (310347@main) (143722975)
• Fixed an issue where URL fragments were not percent-decoded before being used for SVG references. (310443@main) (169582378)

Scrolling

Resolved Issues

• Fixed an issue where sticky-positioned elements could flicker rapidly after scrolling. (310545@main) (173680821)
• Fixed an issue where scroll anchoring could cause a page to scroll to the top or bottom automatically. (310574@main) (173885027)

Tables

Resolved Issues

• Fixed an issue with a collapsed border color mismatch when the table cell has a different writing-mode. (310303@main) (173655092)

Web API

New Features

• Added support for getAllRecords() and IDBGetAllOptions in the IndexedDB API. (310462@main) (173881825)

Resolved Issues

• Fixed an issue where document.open() incorrectly aliased the caller’s security origin. (310543@main) (173369038)
• Fixed an issue where Object.prototype could not be serialized by structuredClone(). (310363@main) (173728983)
• Fixed an issue where backslashes were not handled correctly in non-special URLs. (310290@main) (173757759)
• Fixed a URL parsing bug in the special relative or authority state. (310300@main) (173772241)
• Fixed an issue where event listener once and passive flags were not preserved when copying listeners between elements. (310355@main) (173834642)
• Fixed `Preserve existing listener options (such as passive defaulting) when overwriting event handler attributes. (310362@main) (173842822)

WebRTC

New Features

• Added support for RTCRtpReceiver.jitterBufferTarget. (310285@main) (173676035)
• Added support for video source width and height in RTC stats. (310295@main) (173677615)

Resolved Issues

• Fixed an issue where I420 BT709 VideoFrame was encoded in an incorrect color space when encoding to VP9. (310306@main) (169425608)
• Fixed an issue where RTCRtpSender.setParameters did not clear parameters that were unset by the web application. (310286@main) (173678165)