Release Notes for Safari Technology Preview 30

Safari Technology Preview Release 30 is now available for download for macOS Sierra. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. This release covers WebKit revisions 215859-216643.


  • Implemented Subresource Integrity (SRI) (r216347)
  • Implemented X-Content-Type-Options:nosniff (r215753, r216195)
  • Added support for Unhandled Promise Rejection events (r215916)
  • Updated document.cookie to only return cookies if the document URL has a network scheme or is a file URL (r216341)
  • Removed the non-standard document.implementation.createCSSStyleSheet() API (r216458)
  • Removed the non-standard Element.scrollByLines() and scrollByPages() (r216456)
  • Changed to allow a null comparator in Array.prototype.sort (r216169)
  • Changed to set the Response.blob() type based on the content-type header value (r216353)
  • Changed Element.slot to be marked as [Unscopable] (r216228)
  • Implemented HTMLPreloadScanner support for <link preload> (r216143)
  • Fixed setting Response.blob() type correctly when the body is a ReadableStream (r216073)
  • Moved offsetParent, offsetLeft, offsetTop, offsetWidth, offsetHeight properties from Element to HTMLElement (r216466)
  • Moved the style property from Element to HTMLElement and SVGElement, then made it settable (r216426)


  • Fixed Arrow function access to this after eval('super()') within a constructor (r216329)
  • Added support for dashed values in unicode locale extensions (r216122)
  • Fixed the behaviour of the .sort(callback) method to match Firefox and Chrome (r216137)


  • Fixed space-evenly behavior with Flexbox (r216536)
  • Fixed font-stretch:normal to select condensed fonts (r216517)
  • Fixed custom properties used in rgb() with calc() (r216188)


  • Fixed the behavior of aria-orientation="horizontal" on a list (r216452)
  • Prevented exposing empty roledescription (r216457)
  • Propagated aria-readonly to grid descendants (r216425)
  • Changed to ignore aria-rowspan value if a rowspan value is provided for a <td> or <th> (r216167)
  • Fixed an issue causing VoiceOver to skip cells after a cell with aria-colspan (r216134)
  • Changed to treat cells with ARIA table cell properties as cells (r216123)
  • Updated implementation of aria-orientation to match specifications (r216089)

Web Inspector

  • Added resource load error reason text in the details sidebar (r216564)
  • Fixed toggling the Request and Response resource views in certain cases (r216461)
  • Fixed miscellaneous RTL and localization issues (r216465, r216629)
  • Fixed Option-Click on URL behavior in Styles sidebar (r216166)
  • Changed 404 Image Loads to appear as a failures in Web Inspector (r216138)


  • Fixed several issues that prevented cookie-related endpoints from working correctly (r216258, r216261, r216292)


  • Removed black background from video layer while in fullscreen (r216472)


  • Fixed problem with the CSS Font Loading API’s load() function erroneously resolving promises when used with preinstalled fonts (r216079)
  • Fixed flickering on asynchronous image decoding and ensured the image is incrementally displayed as new data is received (r216471)