# Safari Technology Preview 29 Release Notes Preview the latest web technology updates including: JavaScript, CSS, Rendering, Web Inspector, WebCrypto, Accessibility, Media, and bug fixes. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 29 is now [available for download](https://webkit.org/downloads/) 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 [215271-215859](https://trac.webkit.org/log?stop_rev=215271&rev=215859&limit=589). ### JavaScript - Implemented `Intl.DateTimeFormat.prototype.formatToParts` ([r215616](https://trac.webkit.org/changeset/215616)) - Improved `Date.parse` to accept wider range of date strings ([r215359](https://trac.webkit.org/changeset/215359)) - Implemented `Object.isFrozen()` and `Object.isSealed()` according to ECMA specifications ([r215272](https://trac.webkit.org/changeset/215272)) ### CSS - Added support for percentage gaps for CSS Grid ([r215463](https://trac.webkit.org/changeset/215463)) - Changed `:focus-within` behavior to match specifications ([r215719](https://trac.webkit.org/changeset/215719)) ### Rendering - Avoided repaints for invisible animations on tumblr.com ([r215507](https://trac.webkit.org/changeset/215507)) - Fixed rendering flexbox children across columns ([r215320](https://trac.webkit.org/changeset/215320)) - Fixed `text-align:start` and `text-align:end` behavior in table cells ([r215375](https://trac.webkit.org/changeset/215375)) - Fixed animations with large negative `animation-delays` that fail depending on machine uptime ([r215352](https://trac.webkit.org/changeset/215352)) - Reduced redundant text measuring during mid-word breaking ([r215666](https://trac.webkit.org/changeset/215666)) - Changed memory handling to keep all of the decoded frames for an animated image if the total memory size of the frames is under 30MB (up from 5MB) ([r215557](https://trac.webkit.org/changeset/215557)) - Fixed `

` content inside `

` to wrap mid-word when `word-break:break-word` is set ([r215660](https://trac.webkit.org/changeset/215660)) - Fixed the location of the “recent searches” popover of `` in RTL mode ([r215830](https://trac.webkit.org/changeset/215830)) ### Web Inspector - Added regular expression support to XHR breakpoints ([r215584](https://trac.webkit.org/changeset/215584)) - Added a pause reason for “All Requests” XHR breakpoint ([r215427](https://trac.webkit.org/changeset/215427)) - Fixed the enabled state of “All Requests” XHR breakpoint to be correctly restored ([r215435](https://trac.webkit.org/changeset/215435)) - Fixed a bug where XHR breakpoints would disappear when the inspected page is reloaded ([r215473](https://trac.webkit.org/changeset/215473)) - Fixed XHR breakpoints restored from settings but not appearing in the sidebar ([r215422](https://trac.webkit.org/changeset/215422)) - Fixed Network datagrid columns to correctly restore their shown or hidden state ([r215449](https://trac.webkit.org/changeset/215449)) - Added tooltips to Network grid items for easier reading when text overflows ([r215631](https://trac.webkit.org/changeset/215631)) - Fixed sorting by Priority column in Network datagrids ([r215793](https://trac.webkit.org/changeset/215793)) - Fixed the display of Web Socket messages with non-latin letters ([r215388](https://trac.webkit.org/changeset/215388)) - Prevented showing the Search tab for location links, prefer the Resources tab ([r215630](https://trac.webkit.org/changeset/215630)) - Changed to treat Uint8ClampedArray as an array, not an object ([r215855](https://trac.webkit.org/changeset/215855)) - Fixed Command-G (⌘G) shortcut to allow Find next to work in the console ([r215795](https://trac.webkit.org/changeset/215795)) - Implemented autocompletion for CSS variables ([r215358](https://trac.webkit.org/changeset/215358)) - Updated the icon for the Ignore resource cache button in the Network Tab ([r215440](https://trac.webkit.org/changeset/215440)) ### WebCrypto - Added support for ECDSA ([r215423](https://trac.webkit.org/changeset/215423)) - Improved converting an ECDSA signature binary into DER format ([r215791](https://trac.webkit.org/changeset/215791)) ### Accessibility - Changed the role description of `

---

` from “separator” to “rule” ([r215532](https://trac.webkit.org/changeset/215532)) ### Media - Restricted WebKit image formats to a known whitelist ([r215706](https://trac.webkit.org/changeset/215706), [r215829](https://trac.webkit.org/changeset/215829)). WebKit now only loads images of the following formats: - PNG (.png) - GIF (.gif) - JPEG (.jpg), (.jpeg), (.jpe), (.jif), (.jfif), (.jfi) - JPEG 2000 (.jp2), (.j2k), (.jpf), (.jpx), (.jpm), (.mj2) - TIFF (.tiff), (.tif) - MPO (.mpo) - Microsoft Bitmap (.bmp), (.dib) - Microsoft Cursor (.cur) - Microsoft Icon (.ico) ### Bug Fixes - Fixed an issue where the status bar would not display modifier key information (e.g. “Open * in new tab” when holding the Command key) ([r215790](http://trac.webkit.org/r215790)) - Improved performance of typing on pages with many `` elements - Fixed an issue where a hardware “enter” key would not dismiss JavaScript `alert`, `confirm`, or `prompt`; previously, only the “return” key would dismiss a dialog - Fixed QuotaExceededError when saving to localStorage in private browsing mode or WebDriver sessions ([r215315](https://trac.webkit.org/changeset/215315)) - Fixed an issue where the Content-Disposition header filename was ignored when the download attribute is specified ([r215736](https://trac.webkit.org/changeset/215736/webkit)) - Fixed escaping ‘<’ and ‘>’ in attribute values when using `XMLSerializer.serializeToString()` API ([r215648](https://trac.webkit.org/changeset/215648/webkit)) - Fixed issues causing `beforeunload` dialog to be shown even though the user did not interact with the page ([r215404](https://trac.webkit.org/changeset/215404)) - Changed all CORS requests and cross origin access from `file://` to be blocked unless Disable Local File Restrictions is selected from the Develop menu --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)