--- title: Safari Technology Preview 57 Release Notes framework: safari-technology-preview-release-notes role: article role_heading: Article path: safari-technology-preview-release-notes/stp-release-57 --- # Safari Technology Preview 57 Release Notes Preview the latest web technology updates including: JavaScript, Animations, Storage Access API, Security, Media, Accessibility, WebDriver, and Web Inspector. ## Overview Overview Safari Technology Preview Release 57 is now available for download for macOS High 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 231553-232108. This version of Safari Technology Preview will no longer run on macOS Sierra. To continue testing or living on the latest enhancements to Safari and WebKit, please upgrade to macOS High Sierra. JavaScript Added support for Intl.NumberFormat().formatToParts() (r231867) Changed to throw SyntaxErrors for runtime generated regular expressions with errors (r231939) Implemented BigInt support for *, /, and == operations (r231733, r231886, r231629) Improved specification compliance for Internationalization APIs (r231740) Improved the speed of Object.assign for final objects (r231687) Animations Exposed Web Animations CSS integration as an experimental feature (r231798) Fixed a bug where animation-play-state:paused causes very high cpu load because of a style invalidation loop (r231794) Storage Access API Extended the lifetime of cookies on successful user approval (r231684) Security Added initial support for the Cross-Origin-Options HTTP response header (r231622, r231654) Changed Cross-Origin-Options:deny and Cross-Origin-Options:allow-postmessage to prevent getting navigated by cross-origin scripts (r231911) Changed X-Frame-Options:SAMEORIGIN to check all ancestor frames (r231730) Media Enabled the modern EME API by default (r231903) Fixed media continuing to load after rendered invisible (e.g. removed from DOM; scrolled off screen) (r231817) Improved NowPlaying using the element "title" attribute when available (r231866) Accessibility Changed the accessiblility name provided for a node to simplify the whitespace when using innerText (r231627) Excluded hidden nodes which are not directly referenced from participating in name or description content (r231620) Ensured listbox and combobox roles embedded in labels participate in name calculation (r231778) Exposed the primary screen height through the AX API (r231937) Fixed a bug with VoiceOver causing