KHTML is a

browser engine A browser engine (#Name and scope, also known as a layout engine or rendering engine) is a core software component of every major web browser. The primary job of a browser engine is to transform HTML documents and other resources of a web page in ...

developed by the

KDE KDE is an international Free software movement, free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-know ...

project. It is the default engine of the

Konqueror Konqueror is a free and open-source web browser and file manager that provides web access and file-viewer functionality for file systems (such as local files, files on a remote FTP server and files in a disk image). It forms a core part of ...

browser, but it has not been actively worked on since 2016. Moreover, KHTML will be discontinued for

KDE Frameworks KDE Frameworks is a collection of libraries and software frameworks readily available to any Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality solutions like hardware integration, fi ...

6. Built on the

KParts KDE Frameworks is a collection of libraries and software frameworks readily available to any Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality solutions like hardware integration, fi ...

framework and written in

C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...

, KHTML had relatively good support for Web standards during its prime. Engines forked from KHTML are used by some of the world's most widely used browsers, among them

Google Chrome Google Chrome is a cross-platform web browser developed by Google. It was first released in 2008 for Microsoft Windows, built with free software components from Apple WebKit and Mozilla Firefox. Versions were later released for Linux, macOS ...

Safari A safari (; ) is an overland journey to observe wild animals, especially in eastern or southern Africa. The so-called "Big Five" game animals of Africa – lion, leopard, rhinoceros, elephant, and Cape buffalo – particularly form an importa ...

Opera Opera is a form of theatre in which music is a fundamental component and dramatic roles are taken by singers. Such a "work" (the literal translation of the Italian word "opera") is typically a collaboration between a composer and a librett ...

Vivaldi Antonio Lucio Vivaldi (4 March 1678 – 28 July 1741) was an Italian composer, virtuoso violinist and impresario of Baroque music. Regarded as one of the greatest Baroque composers, Vivaldi's influence during his lifetime was widespread a ...

, and

Microsoft Edge Microsoft Edge is a proprietary, cross-platform web browser created by Microsoft. It was first released in 2015 as part of Windows 10 and Xbox One and later ported to other platforms as a fork of Google's Chromium open-source project: Android ...

History

Origins

KHTML was preceded by an earlier engine called ''khtmlw'' or ''the KDE HTML Widget'', developed by Torben Weis and Martin Jones, which implemented support for

HTML The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...

3.2,

HTTP The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...

1.0, and

HTML frames In the context of a web browser, a frame is a part of a web page or browser window which displays content independent of its container, with the ability to load content independently. The HTML or media elements shown in a frame may come from a ...

, but not the

W3C The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...

DOM Dom or DOM may refer to: People and fictional characters * Dom (given name), including fictional characters * Dom (surname) * Dom La Nena (born 1989), stage name of Brazilian-born cellist, singer and songwriter Dominique Pinto * Dom people, an et ...

CSS Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML (including XML dialects such as SVG, MathML or XHTML). CSS is a cornerstone techno ...

, or

JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of Website, websites use JavaScript on the Client (computing), client side ...

. KHTML itself came into existence on November 4, 1998, as a

fork In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods ei ...

of the khtmlw library, with some slight refactoring and the addition of

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology Technical standard, standard for the consistent character encoding, encoding, representation, and handling of Character (computing), text expre ...

support and changes to support the move to Qt 2. Waldo Bastian was among those who did the work of creating that early version of KHTML.

Re-write and improvement

The real work on KHTML actually started between May and October 1999, with the realization that the choice facing the project was "either do a significant effort to move KHTML forward or to use

Mozilla Mozilla (stylized as moz://a) is a free software community founded in 1998 by members of Netscape. The Mozilla community uses, develops, spreads and supports Mozilla products, thereby promoting exclusively free software and open standards, wi ...

" and with adding support for

as the highest priority. So in May 1999, Lars Knoll began doing research with an eye toward implementing the

specification, finally announcing on August 16, 1999 that he had checked in what amounted to a complete rewrite of the KHTML library—changing KHTML to use the standard

as its internal document representation. That in turn allowed the beginnings of

support to be added in October 1999, with the integration of

Harri Porten Harri Porten (born 1972) is a software engineer. Porten, a KDE developer and former Trolltech employee, is the CEO of Froglogic, a consultancy company related to Qt development. He lives in Hamburg, Germany. Porten originally wrote the KJS Ja ...

's KJS following shortly afterwards. In the closing months of 1999 and first few months of 2000, Knoll did further work with Antti Koivisto and Dirk Mueller to add CSS support and to refine and stabilize the KHTML architecture, with most of that work being completed by March 2000. Among other things, those changes enabled KHTML to become the second browser after

Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical user interface, graphical web browsers developed by Microsoft which was used in the Microsoft Wind ...

to correctly support

Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...

and

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

and languages written

right-to-left In a script (commonly shortened to right to left or abbreviated RTL, RL-TB or R2L), writing starts from the right of the page and continues to the left, proceeding from top to bottom for new lines. Arabic, Hebrew, Persian, Pashto, Urdu, Kashmiri ...

—before

had such support. KDE 2.0 was the first KDE release (on October 23, 2000) to include KHTML (as the rendering engine of the new

file File or filing may refer to: Mechanical tools and processes * File (tool), a tool used to ''remove'' fine amounts of material from a workpiece **Filing (metalworking), a material removal process in manufacturing ** Nail file, a tool used to gent ...

and

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

, which replaced the monolithic KDE File Manager).

Other modules

KSVG was first developed in 2001 by Nikolas Zimmermann and Rob Buis; however, by 2003, it was decided to fork the then-current KSVG implementation into two new projects: KDOM/KSVG2 (to improve the state of DOM rendering in KHTML underneath a more formidable SVG 1.0 render state) and Kcanvas (to abstract any rendering done within khtml/ksvg2 in a single shared library, with multiple backends for it, e.g., Cairo/Qt, etc.). KSVG2 is also a part of

WebKit WebKit is a browser engine developed by Apple and primarily used in its Safari web browser, as well as on the iOS and iPadOS version of any web browser. WebKit is also used by the BlackBerry Browser, PlayStation consoles beginning from the PS ...

Sunsetting

KHTML is set to be removed in

6. It has not had active development since 2016, just the necessary maintenance to work with updates to Frameworks 5.

Standards compliance

The following standards are supported by the KHTML engine: *

4.01 *

HTML 5 HTML5 is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and final major HTML version that is a World Wide Web Consortium (W3C) recommendation. The current specification is known as the HTML L ...

support *

1 *

2.1 (screen and paged media) *

3 Selectors (fully as of KDE 3.5.6) *

3 Other (multiple backgrounds, box-sizing and text-shadow) * PNG,

MNG Multiple-image Network Graphics (MNG) is a graphics file format, published in 2001, for animated images. Its specification is publicly documented and there are free software Free software or libre software is computer software distribute ...

JPEG JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and imag ...

GIF The Graphics Interchange Format (GIF; or , see pronunciation) is a bitmap image format that was developed by a team at the online services provider CompuServe led by American computer scientist Steve Wilhite and released on 15 June 1987. ...

graphic formats *

1, 2 and partially 3 * ECMA-262/JavaScript 1.5 * Partial

Scalable Vector Graphics Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium sinc ...

support

Descendants

KHTML and KJS were adopted by

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

in 2002 for use in the

web browser. Apple publishes the source code for their

of the KHTML engine, called

. In 2013,

Google Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...

began development on a fork of WebKit, called

Blink Blinking is a bodily function; it is a semi-autonomic rapid closing of the eyelid. A single blink is determined by the forceful closing of the eyelid or inactivation of the levator palpebrae superioris and the activation of the palpebral portio ...

References

External links

Web Browser
nbsp;– the Konqueror website
KHTML – KDE's HTML library
nbsp;– description at developer.kde.org

KHTML at the KDE git repository

KHTML bugs fixed in the last year
(self-updating query)
From KDE to WebKit: The Open Source Engine That's Here to Stay
nbsp;– presentation at Yahoo! office by Lars Knoll and George Staikos on December 8, 2006 (video) {{KDE 1999 software Free layout engines Free software programmed in C++ KDE Frameworks KDE Platform