A web browser (commonly referred to as a 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/URL) and may be a web page, image, video or other piece of content. Hyperlinks present in resources enable users easily to navigate their browsers to related resources.
Although browsers are primarily intended to use the World Wide Web, they can also be used to access information provided by web servers in private networks or files in file systems.
The major web browsers are Firefox, Internet Explorer/Microsoft Edge, Google Chrome, Opera, and Safari.
(詳細はTim Berners-Lee. Berners-Lee is the director of the World Wide Web Consortium (W3C), which oversees the Web's continued development, and is also the founder of the World Wide Web Foundation. His browser was called WorldWideWeb and later renamed Nexus.〔(【引用サイトリンク】title=Tim Berners-Lee: WorldWideWeb, the first Web client )〕
The first commonly available web browser with a graphical user interface was Erwise. The development of Erwise was initiated by Robert Cailliau.
In 1993, browser software was further innovated by Marc Andreessen with the release of Mosaic, "the world's first popular browser", which made the World Wide Web system easy to use and more accessible to the average person. Andreesen's browser sparked the internet boom of the 1990s.〔 The introduction of Mosaic in 1993 – one of the first graphical web browsers – led to an explosion in web use. Andreessen, the leader of the Mosaic team at 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).
Microsoft responded with its Internet Explorer in 1995, also heavily influenced by Mosaic, initiating the industry's first browser war. Bundled with Windows, Internet Explorer gained dominance in the web browser market; Internet Explorer usage share peaked at over 95% by 2002.
Opera debuted in 1996; it has never achieved widespread use, having less than 2% browser usage share as of February 2012 according to Net Applications.〔 Its Opera-mini version has an additive share, in April 2011 amounting to 1.1% of overall browser use, but focused on 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% of browser use.〔 As of August 2011, Firefox has a 28% usage share.〔(【引用サイトリンク】title=StatCounter Global Stats - Browser, OS, Search Engine including Mobile Usage Share )〕
Apple's Safari had its first beta release in January 2003; as of April 2011, it had a dominant share of Apple-based web browsing, accounting for just over 7% of the entire browser market.〔
The most recent major entrant to the browser market is Chrome, first released in September 2008. Chrome's take-up has increased significantly year by year, by doubling its usage share from 8% to 16% by August 2011. This increase seems largely to be at the expense of Internet Explorer, whose share has tended to decrease from month to month.〔(【引用サイトリンク】title=Internet Explorer usage to plummet below 50 percent by mid-2012 )〕 In December 2011, Chrome overtook Internet Explorer 8 as the most widely used web browser but still had lower usage than all versions of Internet Explorer combined. Chrome's user-base continued to grow and in May 2012, Chrome's usage passed the usage of all versions of Internet Explorer combined.〔(【引用サイトリンク】title=StatCounter Global Stats - Browser, OS, Search Engine including Mobile Usage Share )〕 By April 2014, Chrome's usage had hit 45%.〔(【引用サイトリンク】title=StatCounter Global Stats - Browser, OS, Search Engine including Mobile Usage Share )〕
Internet Explorer was deprecated in Windows 10, with Microsoft Edge replacing it as the default web browser.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』