Release Notes for Safari Technology Preview 170

Learn about the latest web technology updates in Safari Technology Preview: CSS, Layout, JavaScript, Media, Popover, and Accessibility.


Safari Technology Preview Release 170 is now available for download for macOS Monterey 12.3 or later and macOS Ventura. If you already have Safari Technology Preview installed, you can update it in the Software Update pane of System Preferences on macOS Monterey, or System Settings under General → Software Update on macOS Ventura.

This release includes WebKit changes between: 263290@main…263537@main.


  • Fixed :dir pseudo-class to invalidate after removing dir content attribute from the document element (263357@main)
  • Fixed computing the percentage height of table cell replaced children where the table cell has a horizontal scrollbar (263318@main)
  • Fixed shorthand flow relative margin and padding values to resolve for individual CSS property values (263372@main, 263391@main)
  • Fixed trimming nested self-collapsing children at block-end (263439@main)
  • Fixed trimmed block-end margins for block containers to be reflected in the computed style in a horizontal writing mode (263398@main)
  • Fixed content at block-start edge to have their trimmed margins reflected in the computed style (263412@main)
  • Fixed the CSS hypot() function sometimes returning the result squared (263351@main)


  • Fixed the value not updating on <meter> and <progress> elements (263473@main)


  • Fixed unexpected content wrapping when percent padding is present (263535@main)
  • Fixed sibling flex items sometimes showing clamped content (263360@main)
  • Fixed incorrect damage line index sometimes causing double inline items (263455@main)
  • Fixed content getting truncated too early caused by subpixel flooring (263428@main)
  • Fixed text-overflow: ellipsis truncating the text incorrectly in right-to-left (263418@main)


  • Expanded existing property names caching onto Reflect.ownKeys() and Object.getOwnPropertySymbols() (263441@main)
  • Integrated inlined megamorphic access in DFG and FTL (263300@main)
  • Optimized Object.assign with empty object (263444@main)
  • Simplified and optimized the JSON parser (263416@main)


  • Fixed content briefly zooming in when exiting picture-in-picture (263350@main)
  • Fixed AirPlay sometimes failing (263534@main)


  • Fixed handling of popovers moved between documents after beforetoggle event (263449@main)
  • Implemented focus navigation scopes for popovers (263532@main)


  • Fixed aria-flowto for display: contents elements (263425@main)
  • Fixed display: contents elements never returning any selected AX children despite having them (263339@main)
  • Fixed the accessible name getting computed incorrectly for display: contents elements that rely on labels or captions (263379@main)
  • Fixed form controls to be focusable when tabindex attribute is set (263527@main)