A web browser or Internet browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier (URI) and may be a web page, image, video, or other piece of content.1 Hyperlinks present in resources enable users to easily navigate their browsers to related resources. Although browsers are primarily intended to access the World Wide Web, they can also be used to access information provided by Web servers in private networks or files in file systems. Some browsers can also be used to save information resources to file systems. Contents 1 History 2 Function 3 Features 3.1 User interface 3.2 Privacy and security 3.3 Standards support 4 See also 5 References 6 External links // History Main article: History of the web browser WorldWideWeb for NeXT, released in 1991, was the first Web browser.2 The history of the Web browser dates back in to the late 1980s, when a variety of technologies laid the foundation for the first Web browser, WorldWideWeb, by Tim Berners-Lee in 1991. That browser brought together a variety of existing and new software and hardware technologies. Ted Nelson and Douglas Engelbart developed the concept of hypertext long before Berners-Lee and CERN. It became the core of the World Wide Web. Berners-Lee does acknowledge Engelbart's contribution. The introduction of the NCSA Mosaic Web browser in 1993 – one of the first graphical Web browsers – led to an explosion in Web use. Marc Andreessen, the leader of the Mosaic team at the National Center for Supercomputing Applications (NCSA), soon started his own company, named Netscape, and released the Mosaic-influenced Netscape Navigator in 1994, which quickly became the world's most popular browser, accounting for 90% of all Web use at its peak (see usage share of web browsers). "In the Web's first generation, Tim Berners-Lee launched the Uniform Resource Locator (URL), Hypertext Transfer Protocol (HTTP), and HTML standards with prototype Unix-based servers and browsers. A few people noticed that the Web might be better than Gopher. In the second generation, Marc Andreessen and Eric Bina developed NCSA Mosaic at the University of Illinois. Several million then suddenly noticed that the Web might be better than sex. In the third generation, Andreessen and Bina left NCSA to found Netscape..."

Bob Metcalfe, InfoWorld, August 21, 1995, Vol. 17, Issue 34. 3 Microsoft responded with its browser Internet Explorer in 1995 (also heavily influenced by Mosaic), initiating the industry's first browser war. By bundling Internet Explorer with Windows, Microsoft was able to leverage its dominance in the operating system market to take over the Web browser market; Internet Explorer usage share peaked at over 95% by 2002.4 The usage share of Internet Explorer has declined from over 62.1% in January 2010 to 57.1% in December 2010 according to Net Applications, and it continues to decline.5 Opera first appeared in 1996; although it has never achieved widespread use, with a browser usage share that has fluctuated between 2.2% and 2.4% throughout 2010,5 it has a substantial share of the fast-growing mobile phone Web browser market, being preinstalled on over 40 million phones. It is also available on several other embedded systems, including Nintendo's Wii video game console. In 1998, Netscape launched what was to become the Mozilla Foundation in an attempt to produce a competitive browser using the open source software model. That browser would eventually evolve into Firefox, which developed a respectable following while still in the beta stage of development; shortly after the release of Firefox 1.0 in late 2004, Firefox (all versions) accounted for 7.4% of browser use.4 The Firefox usage share has slowly declined in 2010, from 24.4% in January to 22.8% in December.5 Apple's Safari had its first beta release in January 2003; it has a dominant share of Apple-based Web browsing, having risen from 4.5% usage share in January 2010 to 5.9% in December 2010.5 Its rendering engine, called WebKit, is also running in the standard browsers of several mobile phone platforms, including Apple iOS, Google Android, Nokia S60 and Palm webOS. The most recent major entrant to the browser market is Google's WebKit-based Chrome, first released in September 2008. Its market share has quickly risen; its usage share has nearly doubled from 5.2% in January 2010 to 10.0% in December 2010, and appears to be gaining further in the coming months.5 Function

The primary purpose of a web browser is to bring information resources to the user. This process begins when the user inputs a Uniform Resource Identifier (URI), for example http://en.wikipedia.org/, into the browser. The prefix of the URI determines how the URI will be interpreted. The most commonly used kind of URI starts with http: and identifies a resource to be retrieved over the Hypertext Transfer Protocol (HTTP). Many browsers also support a variety of other prefixes, such as https: for HTTPS, ftp: for the File Transfer Protocol, and file: for local files. Prefixes that the web browser cannot directly handle are often handed off to another application entirely. For example, mailto: URIs are usually passed to the user's default e-mail application and news: URIs are passed to the user's default newsgroup reader. In the case of http, https, file, and others, once the resource has been retrieved the web browser will display it. HTML is passed to the browser's layout engine to be transformed from markup to an interactive document. Aside from HTML, web browsers can generally display any kind of content that can be part of a web page. Most browsers can display images, audio, video, and XML files, and often have plug-ins to support Flash applications and Java applets. Upon encountering a file of an unsupported type or a file that is set up to be downloaded rather than displayed, the browser prompts the user to save the file to disk. Interactivity in a web page can also be supplied by JavaScript, which usually does not require a plugin. JavaScript can be used along with other technologies to allow "live" interaction with the web page's server via Ajax. In the most advanced browsers, JavaScript programs can produce interactive 2D graphics using the canvas API and fully rendered 3D graphics using WebGL. Information resources may contain hyperlinks to other information resources. Each link contains the URI of a resource to go to. When a link is clicked, the browser navigates to the resource indicated by the link's target URI, and the process of bringing content to the user begins again. Features For more details on this topic, see Comparison of web browsers.

Available web browsers range in features from minimal, text-based user interfaces with bare-bones support for HTML to rich user interfaces supporting a wide variety of file formats and protocols. Browsers which include additional components to support e-mail, Usenet news, and Internet Relay Chat (IRC), are sometimes referred to as "Internet suites" rather than merely "web browsers".678 All major web browsers allow the user to open multiple information resources at the same time, either in different browser windows or in different tabs of the same window. Major browsers also include pop-up blockers to prevent unwanted windows from "popping up" without the user's consent.9101112 Most web browsers can display a list of web pages that the user has bookmarked so that the user can quickly return to them. Bookmarks are also called "Favorites" in Internet Explorer. In addition, all major web browsers have some form of built-in web feed aggregator. In Mozilla Firefox, web feeds are formatted as "live bookmarks" and behave like a folder of bookmarks corresponding to recent entries in the feed.13 In Opera, a more traditional feed reader is included which stores and displays the contents of the feed.14 Furthermore, most browsers can be extended via plug-ins, downloadable components that provide additional features. User interface A typical web browser's interface Most major web browsers have these user interface elements in common:15 Back and forward buttons to go back to the previous resource and forward again. A history list, showing resources previously visited in a list (typically, the list is not visible all the time and has to be summoned) A refresh or reload button to reload the current resource. A stop button to cancel loading the resource. In some browsers, the stop button is merged with the reload button. A home button to return to the user's home page An address bar to input the Uniform Resource Identifier (URI) of the desired resource and display it. A search bar to input terms into a search engine A status bar to display progress in loading the resource and also the URI of links when the cursor hovers over them, and page zooming capability.

Major browsers also possess incremental find features to search within a web page. Privacy and security Most browsers support HTTP Secure and offer quick and easy ways to delete the web cache, cookies, and browsing history. For a comparison of the current security vulnerabilities of browsers, see comparison of web browsers. Standards support Early web browsers supported only a very simple version of HTML. The rapid development of web browsers led to the development of non-standard dialects of HTML, leading to problems with interoperability. Modern web browsers support a combination of standards-based and de facto HTML and XHTML, which should be rendered in the same way by all browsers. See also Internet portal Browser wars Geobrowsing Layout engine Web navigation References ^ Jacobs, Ian; Walsh, Norman (15 December 2004). "URI/Resource Relationships". Architecture of the World Wide Web, Volume One. World Wide Web Consortium. http://www.w3.org/TR/webarch/#id-resources. Retrieved 30 June 2009.  ^ Stewart, William. "Web Browser History". http://www.livinginternet.com/w/wi_browse.htm. Retrieved 5 May 2009.  ^ Roads and Crossroads of Internet History Chapter 4: Birth of the Web ^ a b Searchenginejournal.com ^ a b c d e Hitslink.com ^ "The SeaMonkey Project". Mozilla Foundation. 7 November 2008. http://www.seamonkey-project.org/. Retrieved 30 June 2009.  ^ "Cyberdog: Welcome to the 'doghouse!". 5 July 2009. http://www.cyberdog.org/. Retrieved 30 June 2009.  ^ Teelucksingh, Dev Anand. "Interesting DOS programs". Opus Networkx. http://www.opus.co.tt/dave/internet.htm. Retrieved 30 June 2009.  ^ Andersen, Starr; Abella, Vincent (15 September 2004). "Part 5: Enhanced Browsing Security". Changes to Functionality in Microsoft Windows XP Service Pack 2. Microsoft. http://technet.microsoft.com/en-us/library/bb457150.aspx#EEAA. Retrieved 30 June 2009.  ^ "Pop-up blocker". Mozilla Foundation. http://support.mozilla.com/en-US/kb/Pop-up+blocker. Retrieved 30 June 2009.  ^ "Safari: Using The Pop-Up Blocker". Mac Tips and Tricks. WeHostMacs. 2004. http://www.mactipsandtricks.com/tips/display.lasso?mactip=137. Retrieved 30 June 2009.  ^ "Simple settings". Opera Tutorials. Opera Software. http://www.opera.com/browser/tutorials/settings/#tabs. Retrieved 30 June 2009.  ^ Bokma, John. "Mozilla Firefox: RSS and Live Bookmarks". http://johnbokma.com/firefox/rss-and-live-bookmarks.html. Retrieved 30 June 2009.  ^ "RSS newsfeeds in Opera Mail". Opera Software. http://www.opera.com/mail/rss/. Retrieved 30 June 2009.  ^ "About Browsers and their Features". SpiritWorks Software Development. http://www.about-the-web.com/shtml/browsers.shtml. Retrieved 5 May 2009.  External links Architecture of the World Wide Web, Volume One WorldWideWeb: Proposal for a HyperText Project What is browser? Video by Google How browsers work 50 different browsers in one place v · d · eCloud computing Clients Browsers  · Devices (Netbooks  · Tablets  · Smartphones)  · Operating Systems (Android  · iOS  · Windows Phone 7  · Linux) Applications Google Apps  · Microsoft Online  · NetSuite  · Salesforce Platforms App Engine  · Azure  · Engine Yard  · Force.com  · Heroku  · MTurk  · RightScale  · S3  · SimpleDB  · SQS Infrastructure EC2  · Eucalyptus  · FlexiScale  · GoGrid  · Nimbus  · Rackspace Cloud  · VPC Technologies Networking  · Security  · Datacenters  · Cloud storage  · Internet  · Structured storage  · Virtualization  · Web Services  · Virtual Appliance v · d · eWeb browsers Comparison · History · List (for Unix) · Timeline · Usage share Desktop Internet Explorer shell AOL Explorer · Avant · Deepnet Explorer · Enigma · GreenBrowser · IEs4Linux · Maxthon · MenuBox · NeoPlanet · NetCaptor · Netscape 8 · Internet Explorer (1, 2, 3, 4, 5, 6, 7, 8; 9) · MediaBrowser · Sleipnir · SlimBrowser · SpaceTime · UltraBrowser · WebbIE · ZAC Browser Gecko-based AmiZilla · AT&T Pogo · Beonex Communicator · Camino · Classilla · Conkeror · Epic · Epiphany (2.26.3 and below) · Flock (versions before 3.0) · Galeon · Ghostzilla · GNU IceCat · Gnuzilla · Gollum browser · K-Meleon · Kazehakase · Kirix Strata · Kylo · Mozilla · Mozilla Firefox (2, 3, 3.5, 3.6, 4) · Netscape (6, 7, 8, 9) · SeaMonkey · Skyfire · Sleipnir · Swiftfox · Swiftweasel · Timberwolf · Wyzo · XeroBank Browser WebKit-based Arora · Chrome · Chromium · Dragon · Epiphany (2.28+) · Flock (3.0+) · Fluid · iCab · Maxthon 3 · Midori · OmniWeb · Origyn Web Browser · Rekonq · RockMelt · Safari · Shiira · SRWare Iron · Steam overlay · Steel · Teashark · WebPositive · Uzbl Presto-based Opera (Opera 10) · Nintendo DS & DSi Browser · Internet Channel Java-based HotJava · Lobo · X-Smiles KHTML-based Konqueror · Sputnik Tasman-based Internet Explorer for Mac · MSN for Mac OS X Text-based ELinks · Emacs/W3 · Line Mode Browser · Links (ALynx) · Lynx · Net-Tamer · w3m · WebbIE Other 3B · abaco · Amaya · Arachne · Arena · Charon · Dillo · EGBrowser · Gazelle · IBM Home Page Reader · IBrowse · Internet Explorer for UNIX · KidZui · Lunascape · Mosaic-CK · Mothra · NetPositive · Netscape Communicator · NetSurf · Oregano · VMS Mosaic Mobile Blazer · Bolt browser · Firefox for mobile · Galio · IbisBrowser · Internet Explorer Mobile · Iris Browser · Konqueror Embedded · MicroB · Minimo · NetFront · Obigo Browser · Opera Mobile · Pixo · S60 web browser · Safari · Steel · ThunderHawk · UC Browser · WinWAP · Deepfish · JOCA · Opera Mini · Skyfire · Skweezer · Teashark · uZard Web · Vision Offline readers‎ HTTrack Features Ad filtering · Augmented browsing · Download manager · Cookies · Favicon · Incremental search · bookmarks (Bookmarklet, Live bookmark, Smart Bookmark) · Privacy mode · Tabbed browsing · Universal Edit Button Web standards Acid tests · Cascading Style Sheets · HTML · HTML5 · OCSP · SVG · XHTML Related articles World Wide Web · Widget · Rich Internet application · Site-specific browser · Internet suite · Mobile Web · Net Applications · BrowserChoice.eu · Pwn2Own italics = No longer in development v · d · eEarly web browsers (up to 1996) Comparison  · History  · List (for Unix)  · Timeline  · Usage share 1991 WorldWideWeb (Nexus) · Line Mode Browser (libwww) 1992 ViolaWWW · Erwise · MidasWWW · MacWWW (Samba) · tkWWW 1993 NCSA Mosaic · AMosaic · VMS Mosaic · Cello · Lynx (2.0) · Arena 1994 IBM WebExplorer · Netscape Navigator · MicroMind SlipKnot (1.0) · TradeWave MacWeb · IBrowse · Navipress · Argo · Minuet · AIR Mosaic(Internet in a Box) · Spyglass Mosaic · TCP/Connect II · ANT Fresco 1995 Internet Explorer 1 · Netscape Navigator 2.0 · OmniWeb · WebRouser · Sun WebRunner (HotJava) · Grail · Internet Explorer 2 · Delrina Cyberjack · AOL Web Browser for Macintosh · eWorld Web Browser for Macintosh · NetShark · WebShark · Opera · AMSD Ariadna · UdiWWW · ALynx 1996 Arachne 1.0 · Internet Explorer 3 · Netscape Navigator 3.0 · Oracle PowerBrowser · Apple Cyberdog · INRIA Amaya (.9) · AWeb · VaporWare Voyager · tcpCONNECT4 Related technologies and concepts 3D Markup Language for Web · Aliweb · ARPANET · ASCII · BITNET · Browser wars · CompuServe · Email · Elm · File Transfer Protocol · Gopher · HyperCard · HTML · HyTelnet · libwww · NCSA Telnet · NLS · Prodigy · Teletext · Telnet · Usenet · UUCP · Videotex · Viewdata · Virtual Reality Markup Language · Web page · Whole Internet User's Guide and Catalog · World Wide Web · X.25 v · d · eInternet suites Current AOL Desktop · Arachne · Classilla · Gnuzilla · MSN Explorer · Opera · SeaMonkey Discontinued AOL OpenRide · Beonex Communicator · Cyberdog · Cyberjack · Internet Explorer 3, 4, 5 · Minuet · Mozilla · Netscape 5 · Netscape 6 & 7 · Netscape Communicator Related technologies HyperCard · Gopher · E-mail · Elm · Viewdata · Teletext · Videotex · X.25 · Aliweb · ASCII · HyperText Markup Language · HyTelnet · Libwww · Virtual Reality Markup Language · File Transfer Protocol · Telnet · NLS · NCSA Telnet · UUCP · Usenet · ARPANET · BITNET · Prodigy · CompuServe · 3D Markup Language for Web Related articles Browser wars · Web page · World Wide Web · Whole Internet User's Guide and Catalog · List of web browsers · List of web browsers for Unix/Linux · Comparison of web browsers · Usage share of web browsers · Timeline of web browsers