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1、World Wide WebThe World Wide Web (commonly abbreviated as the Web) is a system of interlinked hypertext documents accessed via the Internet. With a Web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks. Using concep
2、ts from earlier hypertext systems, the World Wide Web was started in 1989 by the English physicist Sir Tim Berners-Lee, now the Director of the World Wide Web Consortium, and later by Robert Cailliau, a Belgian computer scientist, while both were working at CERN in Geneva, Switzerland. In 1990, they
3、 proposed building a web of nodes storing hypertext pages viewed by browsers on a network, and released that web in December. Connected by the existing Internet, other websites were created, around the world, adding international standards for domain names & the HTML language. Since then, Berners-Le
4、e has played an active role in guiding the development of Web standards (such as the markup languages in which Web pages are composed), and in recent years has advocated his vision of a Semantic Web.The World Wide Web enabled the spread of information over the Internet through an easy-to-use and fle
5、xible format. It thus played an important role in popularizing use of the Internet. Although the two terms are sometimes conflated in popular use, World Wide Web is not synonymous with Internet. The Web is an application built on top of the Internet.HistoryIn March 1989, Berners-Lee wrote a proposal
6、 which referenced ENQUIRE and described a more elaborate information management system. With help from Robert Cailliau, he published a more formal proposal (on November 12, 1990) to build a Hypertext project called WorldWideWeb (one word, also W3) as a web of nodes with hypertext documents to store
7、data. That data would be viewed in hypertext pages (webpages) by various browsers (line-mode or full-screen) on the computer network, using an access protocol connecting the Internet and DECnet protocol worlds.The proposal had been modeled after EBTs (Electronic Book Technology, a spin-off from the
8、Institute for Research in Information and Scholarship at Brown University) Dynatext SGML reader that CERN had licensed. The Dynatext system, although technically advanced (a key player in the extension of SGML ISO 8879:1986 to Hypermedia within HyTime), was considered too expensive and with an inapp
9、ropriate licensing policy for general HEP (High Energy Physics) community use: a fee for each document and each time a document was changed.A NeXT Computer was used by Berners-Lee as the worlds first Web server and also to write the first Web browser, WorldWideWeb, in 1990. By Christmas 1990, Berner
10、s-Lee had built all the tools necessary for a working Web: the first Web browser (which was a Web editor as well), the first Web server, and the first Web pages which described the project itself.On August 6, 1991, he posted a short summary of the World Wide Web project on the alt.hypertext newsgrou
11、p. This date also marked the debut of the Web as a publicly available service on the Internet.The first server outside Europe was set up at SLAC in December 1991. The crucial underlying concept of hypertext originated with older projects from the 1960s, such as the Hypertext Editing System (HES) at
12、Brown University- among others Ted Nelson and Andries van Dam- Ted Nelsons Project Xanadu and Douglas Engelbarts oN-Line System (NLS). Both Nelson and Engelbart were in turn inspired by Vannevar Bushs microfilm-based memex, which was described in the 1945 essay As We May Think.Berners-Lees breakthro
13、ugh was to marry hypertext to the Internet. In his book Weaving The Web, he explains that he had repeatedly suggested that a marriage between the two technologies was possible to members of both technical communities, but when no one took up his invitation, he finally tackled the project himself. In
14、 the process, he developed a system of globally unique identifiers for resources on the Web and elsewhere: the Uniform Resource Identifier.The World Wide Web had a number of differences from other hypertext systems that were then available. The Web required only unidirectional links rather than bidi
15、rectional ones. This made it possible for someone to link to another resource without action by the owner of that resource. It also significantly reduced the difficulty of implementing Web servers and browsers (in comparison to earlier systems), but in turn presented the chronic problem of link rot.
16、 Unlike predecessors such as HyperCard, the World Wide Web was non-proprietary, making it possible to develop servers and clients independently and to add extensions without licensing restrictions.On April 30, 1993, CERN announced that the World Wide Web would be free to anyone, with no fees due. Coming two months after the announcement that the Gopher protocol was no longer free to use, this produced a rapid shift away from Gopher
