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by Jason Snell & Dan Moren

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By Jason Snell

Apple rolls out new WebKit features with Safari Technology Preview

Note: This story has not been updated for several years.


Apple will expose major new additions to the web technologies embedded in its Safari web browser on OS X and iOS in a whole new way as a part of a new Safari Technology Preview program it’s launching Wednesday.

Previously, developers were able to download “nightly builds” of WebKit, the open-source technology that powers Safari. With this new program, Apple will be providing a qualified and validated set of releases every two weeks1 to anyone who downloads the Safari Technology Preview. (The updates will be delivered by the familiar Mac App Store software update mechanism.)

And yes, anyone means anyone—the download doesn’t require a developer membership or Apple ID, and the Technology Preview appears as a separate app, allowing developers to run the regular version of WebKit in Safari and the newest preview version side by side.

Apple has recently opened up its software development, making it easy for members of the public to access in-progress versions of iOS and OS X and provide feedback. This announcement, while more developer-centric, seems to be in that same vein. Developers will be able to give feedback to Apple’s WebKit engineering teams early on in the development of new Web features.

The initial release of the Safari Technology Preview features several new technologies not previously released by Apple, including: an implementation of ECMAScript 6, the latest version of JavaScript; a just-in-time JavaScript compiler called B3 that’s optimized for high performance in small Web-based scripts as well as complex Web apps; a revamped version of the IndexedDB technology that allows web apps to better store and manage data; early support for Shadow DOM; support for programmatic cut and copy to the clipboard; and Content Security Policy Level 2.

If IndexedDB sounds familiar to you, you might remember the “Safari is the new IE” blog post by developer Nolan Lawson that was the subject of much discussion last July. Lawson was upset with how poor Apple’s IndexedDB implementation was; it’ll be interesting to see what he thinks of this new implementation. (Update: he seems happy.)

While the Safari Technology Preview runs on the Mac, tools in the product will let developers preview how websites will render and behave on iOS devices as well. And of course, all the technologies Apple builds into WebKit will ultimately be deployed across both OS X and iOS.

Here’s the WebKit blog post on the subject.

  1. Don’t be afraid of the word fortnightly, Apple. 

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