Safari Technology Preview 1 Release Notes

Preview the latest web technology updates including: browser differences, JavaScript improvements, HTML enhancements, and Web Inspector changes.

Overview

Safari Technology Preview is available as a download for macOS Sierra and OS X El Capitan. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab.

Browser Differences

Safari Technology Preview can be run side-by-side with Safari and set as the default browser
Separate local data stores are used for history, bookmarks, cookies, and cache
Browsing history and bookmarks are synced over iCloud when iCloud sync is enabled
The Develop menu is enabled by default
Receives regular updates through the Updates tab of the Mac App Store
Bug reports made on bugreport.apple.com should specify Safari Technology Preview

JavaScript Improvements

ECMAScript 6 support including lexical scoping, iterators, generators, arrow functions, default parameter values and many new built-in APIs
Better standards compliant IndexedDB support with more stability
Included the B3 JavaScript JIT compiler with low-latency, high-throughput that boosts performance
Added the ability to use document.execCommand(‘copy’) and document.execCommand(‘cut’) in response to a user gesture to copy and cut text programmatically

HTML Enhancements

The latest implementation of the Shadow DOM specification
Added support for Content Security Policy Level 2

Web Inspector Changes

Added memory summary and JavaScript allocations timelines
Added a fast JavaScript sampling profiler
Improved JavaScript profiling timeline view

Behavior Changes

Included many web compatibility fixes and bug fixes