Release Notes for Safari Technology Preview 108

Safari Technology Preview Release 108 is now available for download for macOS Catalina and macOS Mojave. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS.

This release covers WebKit revisions 262002-262502.

Web Inspector

  • Network
    • Fixed updating statistics when filtering (r262263)
    • Fixed gaps around the “An error occurred trying to load this resource” message (r262162)
  • Storage
    • Prevented requesting the list of IndexedDB database names multiple times for the same security origin (r262077)
  • Graphics
    • Added support for the id (name) of the animation if it exists (r262404)
    • Fixed populating text editors in the Keyframes section when the Animation panel sidebar in the details sidebar is first shown (r262307)
  • Miscellaneous
    • Fixed ⌘G to not override the current query of the find banner if it’s visible (r262173)


  • Fixed SVG text node’s with content getting described as “empty group” even if it’s not empty (r262500)
  • Fixed ignoring images with an empty alt attribute (r262224)


  • Fixed <area> to require being connected in order to navigate (r262359)
  • Fixed the pageshow event only firing the first time the back button is pressed (r262221)
  • Fixed Array.prototype.splice not setting the length of the returned object if not an Array (r262088)
  • Fixed incorrect location.origin in blob workers (r262026)
  • Implemented ParentNode.prototype.replaceChildren (r262381)


  • Changed the calculation to compute the hypothetical cross size of each item in flexbox to use fit-content, not max-content (r262411)
  • Changed to allow indefinite size flex items to be definite with respect to resolving percentages inside them (r262124)
  • Fixed dynamically setting position: absolute in a grid item to trigger a relayout of that element (r262481)
  • Fixed tables as flex items to obey the flex container sizing (r262378)
  • Fixed styling ::selection for a flex container (r262049)
  • Prevented grid-template-rows from serializing adjacent <line-names> (r262130)
  • Prevented putting out-of-flow boxes in anonymous flex items or grid items (r262061)


  • Fixed BigInt operations to handle exceptions correctly (r262386)


  • Fixed scrolling on a article (r262127)
  • Fixed stuttery overflow scrolling in slow-scrolling regions (r262094)
  • Fixed rendering artifacts when scrolling overlays (r262177)


  • Fixed incorrect clipping of absolute and fixed elements inside stacking-context composited overflow: hidden (r262237)

Async Clipboard API

  • Added support for reading "image/png" on ClipboardItem (r262209)
  • Fixed DataTransfer.prototype.files containing multiple files when pasting a single image with multiple representations (r262047)

Web Animations

  • Avoided starting CSS Transitions for a property when a CSS Animations or JavaScript-originated animation is running for the same property (r262154)
  • Fixed SVG animations to not stop when other animators are still running (r262175)


  • Fixed Picture-in-Picture API issues under stress tests (r262038)
  • Fixed scrubbing video on ( r262169)
  • Fixed fullscreen animation missing a few frames at beginning (r262322)
  • Fixed transition between encrypted and clear codecs throwing an error (r262364)
  • Fixed video freezing when attaching a local MediaStream to multiple elements (r262189)
  • Made setting fullscreen mode more robust under stress tests (r262456)