Apple Developer:開発者向けに「Safari Technology Preview Release 39」配布

Safari Technology PreviewApple

Apple は、開発者向けに「Safari Technology Preview Release 39」を配布したことを通知しています。







Beacon API、Fetch APIなどAPI周りのほかにディレクトリアップロード、JavaScript、WebAssembly、WebRTC、Webインスペクタの修正が行われています。


Release 39

Beacon API

  • Added support for quota limitation
  • Enabled content extensions to be able to intercept Beacon and Ping redirects
  • Improved error reporting
  • Prevented cross origin Beacon requests with an ArrayBuffer or ArrayBufferView payload from doing a CORS preflight

Directory Upload

  • Added basic support for input.webkitdirectory behind an experimental feature flag
  • Added stub File and Directory Entries API interfaces

Fetch API

  • Added support for FetchRequest.body
  • Added support for a callback-based fetch

Input Events

  • Renamed inputType “formatForeColor” to “formatFontColor”
  • Fixed an issue where picking an emoji via the emoji dialog using Control-Command-Space (⌃⌘Space) fires inconsistent beforeinput events.
  • Fixed an issue where using align left or align justify on the Touchbar both send a beforeinput event with the “formatJustifyLeft” inputType.


  • Implemented async generator runtime for async iteration
  • Optimized map iteration for faster performance
  • Added support for the “dotAll” flag for regular expressions


  • Fixed const in unreachable code getting decoded incorrectly, erroneously rejecting the binary as invalid


  • Fixed a MediaStream created without tracks to correctly update the active state after tracks are added

Web Inspector

  • Fixed copying text from the “View variable value” popover in the Styles sidebar
  • Added async stack trace capture when workers or the main context posts a message
  • Replaced “Enter Class Name” input label with “Add New Class” for clarity


  • Implemented HTMLMediaElement dispatch of the onencrypted event
  • Fixed autoplay muted videos not playing when outside the viewport
  • Fixed HTMLTrackElement behavior to match standards