Web browser
From Wikipedia, the free encyclopedia
A Web browser is a software application which enables a user to display and interact with text, images, videos, music, games and other information typically located on a Web page at a Web site on the World Wide Web or a local area network. Text and images on a Web page can contain hyperlinks to other Web pages at the same or different Web site. Web browsers allow a user to quickly and easily access information provided on many Web pages at many Web sites by traversing these links. Web browsers format HTML information for display, so the appearance of a Web page may differ between browsers.
Web browsers are the most-commonly-used type of HTTP user agent. Although browsers are typically used to access the World Wide Web, they can also be used to access information provided by Web servers in private networks or content in file systems.
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[edit] History
The history of the Web browser dates back to late 1980s, when a variety of technologies laid the foundation for the first Web browser, the WorldWideWeb, by Tim Berners-Lee in 1991. That browser brought together a variety of existing and new software and hardware technologies.
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 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 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. [2]
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.[3] As of February 2009, Firefox has a 21.77% usage share.[4]
Opera debuted in 1996; although it has never achieved widespread use, having less than 1% browser usage share as of February 2009,[4] 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 the Nintendo Wii.
Apple's Safari had its first beta release in January 2003; as of February 2009, it has a dominant share of Apple-based Web browsing, accounting for just over 8% of the entire browser market.[4]
The most recent major entrant to the browser market is Google's Chrome, first released in September 2008. As of February 2009, it has a 1.15% usage share.[4]
[edit] Current Web browsers
Some of the Web browsers currently available for personal computers include Internet Explorer, Opera, Mozilla Firefox, Safari,[5] Avant Browser, Konqueror, Lynx, Google Chrome, Maxthon, Flock, Arachne, Epiphany, K-Meleon and AOL Explorer.
[edit] Protocols and standards
Web browsers communicate with Web servers primarily using Hypertext Transfer Protocol (HTTP) to fetch Web pages. HTTP allows Web browsers to submit information to Web servers as well as fetch Web pages from them. The most-commonly-used version of HTTP is HTTP/1.1, which is fully defined in RFC 2616. HTTP/1.1 has its own required standards that Internet Explorer does not fully support, but most other current-generation Web browsers do.
Pages are located by means of a URL (Uniform Resource Locator, RFC 1738), which is treated as an address, beginning with http: for HTTP transmission. Many browsers also support a variety of other URL types and their corresponding protocols, such as gopher: for Gopher (a hierarchical hyperlinking protocol), ftp: for File Transfer Protocol (FTP), rtsp: for Real-time Streaming Protocol (RTSP), and https: for HTTPS (HTTP Secure, which is HTTP augmented by Secure Sockets Layer or Transport Layer Security).
The file format for a Web page is usually HTML (HyperText Markup Language) and is identified in the HTTP protocol using a MIME content type. Most browsers natively support a variety of formats in addition to HTML, such as the JPEG, PNG and GIF image formats, and can be extended to support more through the use of plugins. The combination of HTTP content type and URL protocol specification allows Web-page designers to embed images, animations, video, sound, and streaming media into a Web page, or to make them accessible through the Web page.
Early Web browsers supported only a very simple version of HTML. The rapid development of proprietary Web browsers led to the development of non-standard dialects of HTML, leading to problems with Web 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. No browser fully supports HTML 4.01, XHTML 1.x or CSS 2.1 yet. Many sites are designed using WYSIWYG HTML-generation programs such as Adobe Dreamweaver or Microsoft FrontPage. Microsoft FrontPage often generates non-standard HTML by default, hindering the work of the W3C in promulgating standards, specifically with XHTML and Cascading Style Sheets (CSS), which are used for page layout. Dreamweaver and other more modern Microsoft HTML development tools such as Microsoft Expression Web and Microsoft Visual Studio conform to the W3C standards.
Some of the more popular browsers include additional components to support Usenet news, Internet Relay Chat (IRC), and e-mail. Protocols supported may include Network News Transfer Protocol (NNTP), Simple Mail Transfer Protocol (SMTP), Internet Message Access Protocol (IMAP), and Post Office Protocol (POP). These browsers are often referred to as "Internet suites" or "application suites" rather than merely Web browsers.
[edit] See also
- Acid3
- Browser wars
- Comparison of Web browsers
- History of the Internet
- Layout engine
- List of Web browsers
- Mobile browser
- RSS
- Timeline of Web browsers
- Universal edit button
- Usage share of Web browsers
[edit] References
- ^ Stewart, William. "Web Browser History". http://www.livinginternet.com/w/wi_browse.htm. Retrieved on 2008-02-02.
- ^ http://www.searchenginejournal.com/mozilla-firefox-internet-browser-market-share-gains-to-74/1082/
- ^ http://www.searchenginejournal.com/mozilla-firefox-internet-browser-market-share-gains-to-74/1082/
- ^ Browser Market Share for Q1 2008. Market Share by Net Applications.com.
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