# Safari Technology Preview 6 Release Notes Preview the latest web technology updates including: JavaScript, CSS, Web APIs, Web Inspector, Media, and bug fixes. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 6 is now [available for download](https://webkit.org/downloads/). If you already have Safari Technology Preview installed, you can update from the [Mac App Store’s Updates tab](macappstore://showUpdatesPage). Release 6 of Safari Technology Preview covers WebKit revisions [201084–201541](http://trac.webkit.org/log/?rev=201541&stop_rev=201084&limit=999). ### JavaScript - Added support for trailing commas in function parameters per [draft ECMAScript spec](https://jeffmo.github.io/es-trailing-function-commas/) ([r201488](http://trac.webkit.org/changeset/201488)) - Improved `RegExp` matching when the result array becomes large ([r201451](http://trac.webkit.org/changeset/201451)) - Made `RegExp` throw an exception instead of a crash when matching deeply nested subexpressions ([r201412](http://trac.webkit.org/changeset/201412)) - Made `TypedArray.prototype.slice` no longer throw an exception if no arguments are provided ([r201364](http://trac.webkit.org/changeset/201364)) - Improved performance of `TypedArray` access by 30% in the 64-bit low-level interpreter ([r201335](http://trac.webkit.org/changeset/201335)) - Fixed a regression where `String.prototype.replace` would fail after being used many times with different replace values ([r201254](http://trac.webkit.org/changeset/201254)) - Improved integer to float conversion code generation in the [B3 JIT Compiler](https://webkit.org/blog/5852/introducing-the-b3-jit-compiler/) ([r201208](http://trac.webkit.org/changeset/201208)) - Fixed arrow functions as default parameter values so they capture `this` properly ([r201122](http://trac.webkit.org/changeset/201122)) ### CSS - Added support for `normal` keyword value per [draft CSS Box Alignment Module Level 3 spec](http://www.w3.org/TR/css-align-3/) ([r201498](http://trac.webkit.org/changeset/201498)) - Updated the parsing of CSS Grid’s fixed-size per the [draft spec](https://drafts.csswg.org/css-grid/#typedef-fixed-size) ([r201399](http://trac.webkit.org/changeset/201399)) - Made elements with `backdrop-filter` clip when used with `clip-path` or `mask` ([r201374](http://trac.webkit.org/changeset/201374)) - Made changing `border-color` and `border-width` on table cells with `border-collapse: collapse` repaint properly ([r201296](http://trac.webkit.org/changeset/201296)) - Fixed `overflow: hidden` so it always repaints clipped content when overflow changes ([r201407](http://trac.webkit.org/changeset/201407)) ### Web APIs - Started allowing empty strings in the `FontFace` constructor and parse them as if they are omitted ([r201421](http://trac.webkit.org/changeset/201421)) - Stopped firing a `popstate` event with a `null` state when navigating back to a stateless cached page ([r201310](http://trac.webkit.org/changeset/201310)) - Started allowing custom drag-and-drop even without placing data in the pasteboard ([r201227](http://trac.webkit.org/changeset/201227)) ### Web Inspector - Made the split console stay closed when using Inspect Element context menu item ([r201222](http://trac.webkit.org/changeset/201222)) - Fixed a regression where CSS properties modified via JavaScript didn’t update in the DOM tree or Styles sidebar ([r201192](http://trac.webkit.org/changeset/201192)) - Improved garbage collection time by 2x when recording heap snapshots ([r201520](http://trac.webkit.org/changeset/201520)) - Made heap snapshot views remove objects that have been garbage collected ([r201183](http://trac.webkit.org/changeset/201183)) - Corrected how transitively dominated objects in heap snapshots display their retained size ([r201477](http://trac.webkit.org/changeset/201477)) - Made [ShadowChicken](https://webkit.org/blog/6240/ecmascript-6-proper-tail-calls-in-webkit/) properly handle when the entry stack frame is a tail deleted frame ([r201465](http://trac.webkit.org/changeset/201465)) - Added indicators to show nesting levels for DOM elements in the *Elements* tab ([r201454](http://trac.webkit.org/changeset/201454)) - Fixed a regression where WebSQL databases were no longer shown in the *Storage* tab on first open ([r201409](http://trac.webkit.org/changeset/201409)) - Improved load time of Web Inspector by profiling with Web Inspector ([r201245](http://trac.webkit.org/changeset/201245)) - Fixed resuming the debugger after breaking on an exception inside a `Promise` callback ([r201211](http://trac.webkit.org/changeset/201211)) - Fixed the main resource not showing up in the *Debugger* tab sidebar after a reload ([r201210](http://trac.webkit.org/changeset/201210)) ### Media - Reduced flicker and jumpiness when entering and exiting fullscreen presentation mode ([r201405](http://trac.webkit.org/changeset/201405), [r201474](http://trac.webkit.org/changeset/201474), [r201530](http://trac.webkit.org/changeset/201530)) ### Bug Fixes - Fixed scrolling on iTunes Connect pages ([r201218](http://trac.webkit.org/changeset/201218)) - Fixed autocorrection so it is easier to type contractions and email addresses ([r201490](http://trac.webkit.org/changeset/201490)) - Fixed a crash during font download failure after garbage collection ([r201358](http://trac.webkit.org/changeset/201358)) - Reverted the change to ignore clicks inside button elements when the mouse moves, due to a regression ([r201292](http://trac.webkit.org/changeset/201292)) - Fixed a regression that broke Zoom In (⌘+) on pages ([r201090](http://trac.webkit.org/changeset/201090)) --- Copyright © 2026 Apple Inc. 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