WebKit is an application framework that provides a foundation upon which to build a web browser. WebKit was originally derived by Apple Inc. from the Konqueror browser's KHTML software library for use as the engine of Mac OS X's Safari web browser and has now been further developed by individuals from the KDE project, Apple, Nokia, Google, Torch Mobile and others. It has been ported to a number of different platforms and is now used as the rendering engine within a number of different pieces of software. WebKit is open source; its WebCore and JavascriptCore components are available under the GNU Lesser General Public License, and WebKit as a whole is available with a BSD-style license.

Origins

WebKit began in 2002 when Apple Inc. created a fork of the KDE project's HTML layout engine KHTML and KDE's JavaScript engine (KJS). Apple developers explained in an email to KDE developersKDE KFM-Devel mailing list "(fwd) Greetings from the Safari team at Apple Computer", January 7, 2003. that these engines allowed easier development than other technologies by virtue of being small (less than 140,000 lines of code), cleanly designed and standards compliant. KHTML and KJS were ported to Mac OS X with the help of an adapter library and renamed WebCore and JavaScriptCore. JavaScriptCore was announced in an email to a KDE mailing list in June 2002, alongside the first release of Apple's changes. WebCore was announced at the Macworld Expo in January 2003 by Apple CEO Steve Jobs with the release of the Safari web browser. JavaScriptCore was first included with Mac OS X v10.2 as a private framework which Apple used within their Sherlock application, while WebCore debuted with the first beta of Safari. Mac OS X v10.3 was the first major release of Apple's operating system to bundle WebKit, although it had already been bundled with a minor release of 10.2.

However, the exchange of code patches between the two branches of KHTML has previously been difficult and the code base diverged because both projects had different approaches in coding. One of the reasons for this is that Apple worked on their version of KHTML for a year before making their fork public.

Despite this, the KDE project was able to incorporate some of these changes to improve KHTML's rendering speed and add features, including compliance with the Acid2 rendering test.Fact: date=August 2008 Konqueror 3.5 passed the Acid2 test, which was released after Apple had opened its WebKit CVS and Bug Database.

According to Apple, some changes involved Mac OS X-specific features (e.g., Objective-C, KWQ, Mac OS X calls) that are absent in KDE's KHTML, which called for different development tactics.

Controversy

At one point KHTML developers said they were unlikely to accept Apple's changes and claimed the relationship between the two groups was a "bitter failure". Apple submitted their changes in large patches that contained a great number of changes with inadequate documentation, often to do with future feature additions. Thus, these patches were difficult for the KDE developers to integrate back into KHTML. Furthermore, Apple had demanded developers to sign nondisclosure agreements before looking at Apple's source code and even then they were unable to access Apple's bug database.