Apple launches new, experimental Safari Technology Preview browser for developers

Safari Technology Preview can now be downloaded from Apple's website and installed on a Mac. While the preview is OS X only, Apple says the software will give developers a look at upcoming Web technologies that will appear in both iOS and OS X.

Safari Technology Preview includes "the latest layout technologies, visual effects, and developer tools." Users can provide input on how they are implemented, helping Apple to improve the Safari experience across all devices.

Highlights of Safari Technology Preview, according to Apple, are:

• Preview the latest web technologies. Get a preview of the latest advances in Safari web technologies, including HTML, JavaScript, and CSS. Safari Technology Preview includes the most recent version of WebKit, the rendering engine that powers Safari.
• Easy to update. You can update Safari Technology Preview right from the Mac App Store. Updates occur every few weeks and include the most recent additions and improvements to WebKit.
• Access powerful developer tools. Use the latest version of the powerful Web Inspector and Responsive Design Mode to modify, debug, and optimize your websites.
• Provide feedback. Use Bug Reporter to send feedback directly to Apple about issues and enhancement requests. Simply select Report an Issue from the Help menu in Safari Technology Preview.
• Run side-by-side with Safari. Safari Technology Preview is a standalone app that works side-by-side with the current version of Safari, so you can continue to use and reference the current release.
• Surf seamlessly with iCloud. Safari Technology Preview works with iCloud, so you can access your latest Safari Favorites, bookmarks, and Reading List.
• Keep current. The WebKit blog keeps you up-to-date on the latest developments in HTML, JavaScript, and CSS.

Though the software is available on Apple's developer website and is only intended for testing purposes, members of the public can also download and install Safari Technology Preview. It requires OS X 10.11.4 or later.

Release 1 has the following accompanying notes:

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