# Safari Technology Preview 227 Release Notes Learn about the latest web technology updates in Safari Technology Preview: Accessibility, Animations, CSS, Editing, Forms, HTML, Images, JavaScript, Networking, Rendering, SVG, Storage, Tables, Web API, Web Inspector, and WebAssembly. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 227 is now [available for download](https://developer.apple.com/safari/resources/) for macOS Tahoe and macOS Sequoia. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update. This release includes WebKit changes between: [298484@main…299099@main](https://github.com/WebKit/WebKit/compare/8b858a5c1c346a4c79899586b752ca7845049f70...c9ff2b60570e45499e67a9cf5d72a7b567850a1f). ### Accessibility #### New Features - Added support for automatically scrolling off-screen `` elements into view when they are focused, improving accessibility for users navigating with screen readers or keyboard shortcuts. ([299075@main](https://commits.webkit.org/299075@main)) (55121458) ### Animations #### New Features - Added support for endpoint-inclusive active intervals in `Animation.commitStyles()` to correctly persist styles for completed animations. ([299031@main](https://commits.webkit.org/299031@main)) (158684709) #### Resolved Issues - Fixed a bug where extremely large `animation-duration` values could cause the page to become unresponsive. ([298975@main](https://commits.webkit.org/298975@main)) (158775366) - Fixed `Animation.commitStyles()` so that custom properties are properly committed to the target element. ([299045@main](https://commits.webkit.org/299045@main)) (158919736) - Fixed `Animation.commitStyles()` to correctly commit logical properties as their corresponding physical properties. ([299046@main](https://commits.webkit.org/299046@main)) (158920529) ### CSS #### New Features - Added support for the `cursor` property on pseudo-elements. ([298777@main](https://commits.webkit.org/298777@main)) (90364915) - Added support for the `position-visibility` property. ([298622@main](https://commits.webkit.org/298622@main)) (129789653) - Added support for the new `math-shift` CSS property to control compact or “cramped” rendering of MathML formulas, reducing vertical shifts for superscripts. ([298839@main](https://commits.webkit.org/298839@main)) (138023006) - Added support for remembering the last successful `position-try` fallback in CSS anchor positioning to reduce layout jumps when styles change. ([298718@main](https://commits.webkit.org/298718@main)) (154352444) - Added support for `position-try` on pseudo-elements like `::before`, `::after`, and `::backdrop`. ([298519@main](https://commits.webkit.org/298519@main)) (156550553) - Added support for non-integral decimal values in the `initial-letter` CSS property to allow fractional sizes. ([298564@main](https://commits.webkit.org/298564@main)) (157808105) - Added support for the `field-sizing` property. ([298511@main](https://commits.webkit.org/298511@main)) (157907105) - Added support for `@scope` implicit scoping roots with constructed and adopted stylesheets to correctly apply styles in shadow DOM. ([298906@main](https://commits.webkit.org/298906@main)) (158119016) - Added support for the `scrollbar-color` property. ([298827@main](https://commits.webkit.org/298827@main)) (158436083) - Added support for the generic `math` font family in `font-family` allowing better default rendering for MathML content. ([299006@main](https://commits.webkit.org/299006@main)) (158851931) #### Resolved Issues - Fixed `getComputedStyle` to correctly ignore `::first-letter` and `::first-line` styles on flex containers, to reflect used style. ([298706@main](https://commits.webkit.org/298706@main)) (94163778) - Fixed `anchor-center` so that when an anchored element has no anchor in the same containing block, it correctly falls back to behaving like `center` as specified. ([298766@main](https://commits.webkit.org/298766@main)) (155768216) - Fixed `anchor()` positioning in CSS Grid to correctly account for `grid-area`. ([298644@main](https://commits.webkit.org/298644@main)) (155823420) - Fixed an issue where changing the `ruby-overhang` property did not trigger a layout update, ensuring proper rendering when overhang values change. ([299091@main](https://commits.webkit.org/299091@main)) (156038239) - Fixed `@media print` styles to work when nested. ([298843@main](https://commits.webkit.org/298843@main)) (158081814) - Fixed automatic `min-size` handling for flex and grid items to correctly treat `overflow: clip` as non-scrollable, aligning with the CSS specifications. ([298690@main](https://commits.webkit.org/298690@main)) (158215991) - Fixed incorrect baseline alignment for `` elements when `contain: layout` is applied by using the content box as the baseline. ([299089@main](https://commits.webkit.org/299089@main)) (159007878) ### Editing #### Resolved Issues - Fixed paste performance in `textarea` by skipping unnecessary layout calls and only removing unrendered text nodes in richly editable fields. ([298505@main](https://commits.webkit.org/298505@main)) (157813510) ### Forms #### New Features - Added support for normalizing full-width digits, minus signs, and full-width dots to ASCII in `` fields, immediately rejecting disallowed characters. ([298613@main](https://commits.webkit.org/298613@main)) (141257181) ### HTML #### New Features - Added support for `command` and `commandfor` attributes on buttons to provide a declarative way to control popovers and dialogs. ([299012@main](https://commits.webkit.org/299012@main)) (147442565) ### Images #### Resolved Issues - Fixed HDR images in CSS backgrounds, CSS borders and inside SVG images so they are now properly decoded and rendered in HDR mode. ([298781@main](https://commits.webkit.org/298781@main)) (158076668) ### JavaScript #### Resolved Issues - Fixed an issue where the module loader would incorrectly attempt to refetch a module after a failed fetch. ([298544@main](https://commits.webkit.org/298544@main)) (158084942) - Fixed `Iterator.prototype.flatMap` to properly handle iterators without a `return` method. ([298966@main](https://commits.webkit.org/298966@main)) (158783404) ### Networking #### Resolved Issues - Fixed an issue where `rel=preload` link headers with a nonce could trigger erroneous `Content-Security-Policy-Report-Only` violations due to the nonce not being copied into the fetch options. ([299070@main](https://commits.webkit.org/299070@main)) (75060055) ### Rendering #### Resolved Issues - Fixed `` elements to use the last line as their baseline instead of the first line to ensure consistent alignment with `
` in the text. ([298518@main](https://commits.webkit.org/298518@main)) (157955703) - Fixed orthogonal table cells so their `writing-mode` is no longer forced to match the table, allowing proper vertical layout. ([298623@main](https://commits.webkit.org/298623@main)) (158221827) - Fixed an issue where the padding end incorrectly contributed to scrollable overflow when the inline direction was flipped. (158529814) - Fixed word breaking so that a hyphen followed by a Latin-1 Supplement character (U+00C0–U+00FF) correctly allows line breaks. ([299051@main](https://commits.webkit.org/299051@main)) (158942361) ### SVG #### New Features - Added support for the `repeatEvent` in SVG animations to align with the SMIL specification and match other browsers. ([298715@main](https://commits.webkit.org/298715@main)) (129919749) - Added support for relative units in SVG. ([299087@main](https://commits.webkit.org/299087@main)) (158634833) #### Resolved Issues - Fixed `SVGMarkerElement` to correctly support the `SVG_MARKER_ORIENT_AUTO_START_REVERSE` value, aligning behavior with the spec and other browsers ([299042@main](https://commits.webkit.org/299042@main)). (123453058) - Fixed handling of `word-spacing` so that leading white space in SVG text correctly applies spacing at the start of a text box. ([299066@main](https://commits.webkit.org/299066@main)) (134941299) - Fixed an issue where SVGs with a `0px` intrinsic width were ignored but now correctly respect degenerate aspect ratios and fall back to the `viewBox` aspect ratio. ([299085@main](https://commits.webkit.org/299085@main)) (156339128) - Fixed `SVGFETurbulenceElement` to correctly fallback `numOctaves` to `1` for invalid or negative values, aligning with the specification and other browsers. ([299083@main](https://commits.webkit.org/299083@main)) (158988528) ### Storage #### Resolved Issues - Fixed WebSockets to correctly inherit storage access from the frame that created them. ([298734@main](https://commits.webkit.org/298734@main)) (147949918) - Fixed an issue where cross-origin navigations incorrectly preserved storage access. ([298820@main](https://commits.webkit.org/298820@main)) (158446697) ### Tables #### Resolved Issues - Fixed collapsed table rows retaining nonzero height. ([298783@main](https://commits.webkit.org/298783@main)) (158276634) ### Web API #### New Features - Added support for enforcing cookie name prefix checks in the `CookieStore` API to reject invalid `__Host-Http-` and `__Http-` names. ([298615@main](https://commits.webkit.org/298615@main)) (156373016) - Added support for `document.activeViewTransition` to expose the current active view transition. ([298550@main](https://commits.webkit.org/298550@main)) (158089900) - Added support for the `scrollend` event. ([298701@main](https://commits.webkit.org/298701@main)) (158158715) - Added support in the Cookie Store API for handling `cookieStore.set` calls with an empty string `path`, defaulting to the current URL path. ([298681@main](https://commits.webkit.org/298681@main)) (158319959) - Added support for the Navigation API. ([298801@main](https://commits.webkit.org/298801@main)). (158433779) #### Resolved Issues - Fixed `CommandEvent` to no longer be composed and updated retargeting to prevent leaking Shadow DOM contents when `event.currentTarget` is null. ([298956@main](https://commits.webkit.org/298956@main)) (150922493) - Fixed JSON modules to fetch with an `application/json` Accept header. ([298595@main](https://commits.webkit.org/298595@main)) (158176845) ### Web Inspector #### Resolved Issues - Fixed an issue where DOM elements represented in the Console could not be selected. ([298834@main](https://commits.webkit.org/298834@main)) (157015598) - Fixed an issue where newlines and indentation in HTML markup would show up in DOM node previews in the Console. ([298626@main](https://commits.webkit.org/298626@main)) (157225532) ### WebAssembly #### New Features - Added support for `WebAssembly.Memory.prototype.toFixedLengthBuffer()` and `.toResizableBuffer()` to enable resizable WebAssembly memory buffers. ([298955@main](https://commits.webkit.org/298955@main)) (147437929) --- 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)