Web browser

A web browser is a computer program used for accessing the World Wide Web. A web browser retrieves and renders webpages to display information stored on a web server. The browser sends an HTTP request to the server, which responds with the requested file. Most web pages are written in HTML, a markup language which allows inclusion of other files; the browser interprets the file and makes additional requests of the server for the additional files, then interprets and displays the results for the user.

Most browsers today are capable of displaying text in HTML, with formatting specified in CSS, images in JPEG, GIF, and PNG formats, scripts written in javascript, animations written in Macromedia's Flash language, and applets written in Java.

Popular Browsers

Internet Explorer

The most popular web browser today is Internet Explorer from Microsoft. Internet Explorer has come bundled with every version of Microsoft's Windows operating system since Windows 95, and is supplied free of charge. Microsoft created versions of Internet Explorer for the Macintosh, Solaris and HP-UX operating systems, but has ceased development on all three versions. The most recent official version is Internet Explorer 7, although Internet Explorer 6 is still supported with Microsoft's extension of Windows XP support until sometime midyear 2008.

Mozilla Firefox

Mozilla Firefox is the second-most popular web browser today. It is the second browser to result from the open-source Mozilla Project started by Netscape corporation to develop a new browser to succeed the Netscape Communicator suite. Versions of Mozilla Firefox are available for the Windows, Macintosh, and Linux operating systems; additionally, as the browser is open-source, volunteers have ported it to Solaris and OS/2.

Opera

The Opera web browser is a browser initially developed by Telenor of Norway. The developers formed Opera Software, and released version 2.1 publically in 1997, at version 2.1. Until 2005, Opera was sold for approximately $25 to $35, though an ad-supported version had appeared earlier for users who did not wish to pay. Since then, it has been available for free. Opera had an early lead in compliance with the CSS standard, and claims to be more standards-compliant than its competitors. Versions of Opera for mobile devices are the default browsers on several mobile phones. Other versions have been developed for video gaming consoles such as the Nintendo Wii.

Konqueror/Safari

The Konqueror web browser was developed for the KDE project for Linux and Unix. Apple developed the Safari web browser for its MacOS X operating system, using the HTML and javascript rendering engines from Konqueror. Apple's rendering engine, WebKit, is open source, and the changes are back-ported to KHTML. Safari was available only for the MacOS X operating system until 11 June 2007, when Apple released a beta version for MacOS X and Windows. Safari was the first Web browser to pass the W3C's Acid2 rendering compatibility test.

History

Tim Berners-Lee on the creation of the web

The very first web brower was a program named WorldWideWeb, developed on a NeXT computer, and released in March 1991. Several other browsers were developed in the subsequent two years, but the most important new browser was NCSA Mosaic, developed by Marc Andreessen and Eric Bina from the NCSA, released in February 1993 on Unix, and later that year for the Macintosh (computer). The 2.0 version of Mosaic, released in January 1994, was the first browser to actually show images embedded in the text, rather than in a separate window.

Other browsers, current and historical

Mozilla

Mozilla is a open-source browser developed from a Netscape codebase. It was the precursor to Mozilla Firefox.

HotJava

HotJava was a browser developed by Sun Microsystems, designed as a proof-of-concept for the Java programming language. The browser was written entirely in Java, and ran Java applets natively.