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Safari Technology Preview 107 Offers The Usual Bug Fixes and Performance Improvements

Safari Technology Preview 107 Offers The Usual Bug Fixes and Performance Improvements

Apple on Thursday released Safari Technology Preview 107, the latest version of their developer preview web browser. The preview version of Apple’s popular browser offers developers and other interested users the ability to try out features that may or may not, debut in future public release versions of Safari.

The new Preview release includes bug fixes and performance improvements for CSS, JavaScript, Media, Web Animations, Accessibility, Rendering, Web API, and Web Inspector.

Release 107

Web Inspector

  • Network
    • Adjusted the spacing of the navigation items so that none are hidden when previewing a resource
  • Sources
    • Added showing the name of the Worker if it exists as the title of its main resource
    • Fixed source mapping issue when combining single-child directory chains
    • Fixed restoring global DOM, URL, or event breakpoints incorrectly enabling all breakpoints
    • Supported CSS pretty printing when a url() is nested inside a url()
  • Timelines
    • Fixed the memory stacked area graph to not extend beyond the “stopping time” marker
  • Storage
    • Fixed requesting the list of IndexedDB database names multiple times for the same security origin
    • Fixed double-clicking on a cookie field to start editing that cookie
  • Layers
    • Ensured that the text at the bottom of the details sidebar doesn’t overlap
  • Console
    • Added showing EventTarget listeners as an internal property
    • Added showing Worker name as an internal property
  • Miscellaneous
    • Accessibility
      • Fixed Left/Right arrow keys to collapse/expand details sections
    • Remote Inspection
      • Provided a way to turn on or off ITP debug mode and AdClickAttribution debug mode
      • Dropped support for iOS 8.x, iOS 9.x, and iOS 10.x


  • Changed the initial value of transform-box to be view-box to fix some SVG animations
  • Fixed computing the correct perspective matrix on a box with borders and overflow: hidden
  • Fixed incorrect location.origin in blob workers
  • Fixed Object.prototype.toString to match standards
  • XML external entity resources should only be loaded from XML MIME types


  • Changed the cursor to update during the rendering steps, rather than on a 20ms timer
  • Fixed the computed min-width and min-height for auto depending on the box
  • Fixed ::selection styling for a flex container
  • Fixed disappearing content with CSS parallax on an overflow scroll


  • Fixed repaint issues when the login field collapses on music.apple.com
  • Fixed text clipped when rendered with fonts which have a negative line gap metric
  • Fixed table sizing when max-width is used


  • Fixed tapping on the trackpad in a <select> to flash the scrollers
  • Fixed a <select> that sometimes becomes non-scrollable
  • Fixed overflow scrollbars not growing when hovered
  • Fixed find not always scrolling search results into view
  • Fixed composited scrolling interfering with the propagation of perspective
  • Fixed scrollbars flickering in RTL scrollable regions


  • Changed to ignore a poster set after playback begins
  • Fixed media controls tracks menu showing “Auto” selected instead of the track selected via the JavaScript API


  • Improved the accuracy of IndexedDB estimated write size computation
  • Fixed a bug that could cause IndexedDB log files to grow without bound


  • Implemented Intl.Locale
  • Implemented BigInt.asIntN and BigInt.asUintN
  • Enabled logical assignment operators
  • Ensured IntlCollator.prototype.resolvedOptions returns relevant locale extension keys in alphabetical order

Web Animations

  • Fixed the animation engine to not wake up every tick for steps() timing functions
  • Fixed animations with a single keyframe not getting accelerated
  • Fixed calling reverse() on an accelerated animation having no effect
  • Coordinated “update animations and send events” procedure across multiple timelines
  • Fixed Document.getAnimations() to only consider document connection and not timeline association
  • Fixed the animation of font-size using rem values

Async Clipboard API

  • Enabled clipboard API access when pasting from a menu item or key binding
  • DataTransfer.files contains multiple files when pasting a single image with multiple representations
  • Fixed cut and paste from Google Doc to Notes in several (non-Latin) languages
  • Preserved character set information when writing to the pasteboard when copying rich text


  • Implemented accessibility of HTML 5.1 Drag & Drop

CSS Grid

  • Cleared the override width for computing percent margins
  • Changed to not create renderers for whitespace nodes
  • Changed to treat percentages as auto for the minimum contribution
  • Fixed auto repeat with multiple tracks and gutters

Bug Fixes

  • Added quirk for cookie blocking latch mode aolmail.com redirecting to aol.com under aol.com
  • Changed to enforce a URL cannot have a username, password, or port if its host is null
  • Changed XML external entities to require an XML MIME type to be loaded
  • Fixed the playhead in Touch Bar continuing when loading stalls
  • Fixed the search field on mayoclinic.org clipping the submit button
  • Fixed setting a host on a URL when no port is specified
  • Limited the HTTP referer to 4KB

The update can be downloaded from the Safari Technology Preview website, or if the browser is already installed, it can be updated via the “Update” tab in the Mac App Store. Full release notes for the update are also available on the Safari Technology Preview website.

While the preview is intended for use by developers and advanced users, in order to provide Apple with feedback on the development of the Safari browser, it can be run side-by-side with the release version of Safari. The app doesn’t require a developer account to download and install. For more information, visit the Safari Technology Preview website.