---
title: Safari Technology Preview 1 Release Notes
framework: safari-technology-preview-release-notes
role: article
role_heading: Article
path: safari-technology-preview-release-notes/stp-release-1
---

# Safari Technology Preview 1 Release Notes

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

## Overview

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

## See Also

### 2016

- [Safari Technology Preview 20 Release Notes](safari-technology-preview-release-notes/stp-release-20.md)
- [Safari Technology Preview 19 Release Notes](safari-technology-preview-release-notes/stp-release-19.md)
- [Safari Technology Preview 18 Release Notes](safari-technology-preview-release-notes/stp-release-18.md)
- [Safari Technology Preview 17 Release Notes](safari-technology-preview-release-notes/stp-release-17.md)
- [Safari Technology Preview 16 Release Notes](safari-technology-preview-release-notes/stp-release-16.md)
- [Safari Technology Preview 15 Release Notes](safari-technology-preview-release-notes/stp-release-15.md)
- [Safari Technology Preview 14 Release Notes](safari-technology-preview-release-notes/stp-release-14.md)
- [Safari Technology Preview 13 Release Notes](safari-technology-preview-release-notes/stp-release-13.md)
- [Safari Technology Preview 12 Release Notes](safari-technology-preview-release-notes/stp-release-12.md)
- [Safari Technology Preview 11 Release Notes](safari-technology-preview-release-notes/stp-release-11.md)
- [Safari Technology Preview 10 Release Notes](safari-technology-preview-release-notes/stp-release-10.md)
- [Safari Technology Preview 9 Release Notes](safari-technology-preview-release-notes/stp-release-9.md)
- [Safari Technology Preview 8 Release Notes](safari-technology-preview-release-notes/stp-release-8.md)
- [Safari Technology Preview 7 Release Notes](safari-technology-preview-release-notes/stp-release-7.md)
- [Safari Technology Preview 6 Release Notes](safari-technology-preview-release-notes/stp-release-6.md)