Release Notes for Safari Technology Preview 77

Safari Technology Preview Release 77 is now available for download for macOS Mojave and macOS High Sierra. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS Mojave and from the Mac App Store’s Updates tab on macOS High Sierra. After updating to macOS Mojave, you may have to reinstall Safari Technology Preview.

This release covers WebKit revisions 241432-242087.


  • Fixed getUserMedia with an ideal deviceId constraint to always select the correct device (r241489)
  • Made navigator.mediaDevices SecureContext (r241602)


  • Fixed WebSocket to not fire events after being stopped (r241599)
  • Fixed Same-Site Lax cookies to be sent with cross-site redirect from a client-initiated load (r241918)
  • Updated the MIME type parser (r241863)

CSS Grid

  • Changed to handle indefinite percentages in fit-content() (r241746)


  • Fixed HTML5 <footer> tag to be read as an ARIA Landmark to VoiceOver (r242051)
  • Fixed incorrectly mapping the <meter> element to progressbar (r241989)


  • Fixed setting fullscreen pseudo-classes outside of root when entering fullscreen from inside of a shadow root (r241484)
  • Changed inline WebVTT styles to start with ::cue (r241608)

Web Inspector

  • Added emulation of user gestures from Web Inspector console (r241633)
  • Added built-in accessibility tests to the Audit tab (r241639)
  • Added a macOS user-agent option in the device settings menu (r241870)
  • Added an experimental setting to merge Resources and Debugger tabs into a single Sources tab (r242049)
  • Changed how selected items are tracked in trees and tables to improve performance (r241652)
  • Changed Command-/ (⌘/) to toggle the edited property in the Styles sidebar (r242063)
  • Changed typing ; to not focus on the next property when there’s open parenthesis or open comment in the Styles sidebar (r241740)
  • Changed clicking a CSS property or selector to always select its text in the Styles sidebar (r241980)
  • Fixed all actions after an offscreen path modification getting marked as offscreen path errors in the Canvas tab (r241616)
  • Fixed an issue where taking a second Canvas recording wouldn’t select the Initial State of the new recording (r241601)
  • Fixed clearing the selection when dragging a selection outside of the selected element in the Console (r242078)
  • Fixed the dim appearance of commas in CSS selectors for dark mode (r241638)
  • Fixed the DOM Content Loaded blue marker for dark mode (r241975)
  • Fixed the Network Overview Graph segments box shadow for dark mode (r242072)
  • Fixed node-specific event breakpoints to get cleared or recalculated on navigation (r241874)
  • Fixed highlighting a node when hovering inside an object preview (r242076)
  • Fixed the navigation sidebar showing “No Search Results” when a slow search is in progress (r242080)
  • Fixed Scripts Timeline loading indicator margins in right-to-left mode (r241857)
  • Fixed valid values in style attributes getting reported as unsupported property values in the Styles sidebar (r241623)
  • Improved the Scripts timeline on-going-recording in dark mode (r241757)
  • Improved categorization of JavaScript Class instances in the Heap Snapshot instances view (r241787)
  • Provided a way to avoid a Timeline recording auto-stop on reload (r241750)
  • Provided a way to make searches case-sensitive or use a regular expression (r242018)

Bug Fixes

  • Fixed a bug that caused loading on some sites to hang in Safari Technology Preview (r241658)

Safari App Extensions

  • Made the window.safari object available in frames opened to safari-extension:// resources