History
Main article: History of the World Wide Web
In March 1989, Tim Berners-Lee wrote a proposal that referenced ENQUIRE, a database and software project he had built in 1980, and described a more elaborate information management system.[10]
With help from Robert Cailliau, he published a more formal proposal (on 12 November 1990) to build a "Hypertext project" called "WorldWideWeb" (one word, also "W3") as a "web" of "hypertext documents" to be viewed by "browsers" using a client–server architecture.[6] This proposal estimated that a read-only web would be developed within three months and that it would take six months to achieve "the creation of new links and new material by readers, [so that] authorship becomes universal" as well as "the automatic notification of a reader when new material of interest to him/her has become available." While the read-only goal was met, accessible authorship of web content took longer to mature, with the wiki concept, blogs, Web 2.0 and RSS/Atom.[11]
The proposal was modeled after the SGML reader Dynatext by Electronic Book Technology, a spin-off from the Institute for Research in Information and Scholarship at Brown University. The Dynatext system, licensed by CERN, was a key player in the extension of SGML ISO 8879:1986 to Hypermedia within HyTime, but it was considered too expensive and had an inappropriate licensing policy for use in the general high energy physics community, namely a fee for each document and each document alteration.
The first web page may be lost, but Paul Jones (computer technologist) of UNC-Chapel Hill in North Carolina revealed in May 2013 that he has a copy of a page given to him by Berners-Lee during a visit to UNC in 1991 which is the oldest known web page. Jones stored it on a magneto-optical drive and on his NeXT computer.[14]
On 6 August 1991, Berners-Lee posted a short summary of the World Wide Web project on the alt.hypertext newsgroup.[15] This date also marked the debut of the Web as a publicly available service on the Internet, although new users only access it after August 23. For this reason this is considered the internaut's day. Many newsmedia have reported that the first photo on the web was uploaded by Berners-Lee in 1992, an image of the CERN house band Les Horribles Cernettes taken by Silvano de Gennaro; Gennaro has disclaimed this story, writing that media were "totally distorting our words for the sake of cheap sensationalism."[16]
The first server outside Europe was set up at the Stanford Linear Accelerator Center (SLAC) in Palo Alto, California, to host the SPIRES-HEP database. Accounts differ substantially as to the date of this event. The World Wide Web Consortium says December 1992,[17] whereas SLAC itself claims 1991.[18][19] This is supported by a W3C document titled A Little History of the World Wide Web.[20]
The crucial underlying concept of hypertext originated with older projects from the 1960s, such as the Hypertext Editing System (HES) at Brown University, Ted Nelson's Project Xanadu, and Douglas Engelbart's oN-Line System (NLS). Both Nelson and Engelbart were in turn inspired by Vannevar Bush's microfilm-based "memex", which was described in the 1945 essay "As We May Think".[21]
Berners-Lee's breakthrough 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 assumed the project himself. In the process, he developed three essential technologies:
- a system of globally unique identifiers for resources on the Web and elsewhere, the universal document identifier (UDI), later known as uniform resource locator (URL) and uniform resource identifier (URI);
- the publishing language HyperText Markup Language (HTML);
- the Hypertext Transfer Protocol (HTTP).[22]
The World Wide Web Consortium (W3C) was founded by Tim Berners-Lee after he left the European Organization for Nuclear Research (CERN) in October 1994. It was founded at the Massachusetts Institute of Technology Laboratory for Computer Science (MIT/LCS) with support from the Defense Advanced Research Projects Agency (DARPA), which had pioneered the Internet; a year later, a second site was founded at INRIA (a French national computer research lab) with support from the European Commission DG InfSo; and in 1996, a third continental site was created in Japan at Keio University. By the end of 1994, while the total number of websites was still minute compared to present standards, quite a number of notable websites were already active, many of which are the precursors or inspiration for today's most popular services.
Connected by the existing Internet, other websites were created around the world, adding international standards for domain names and HTML. Since then, Berners-Lee has played an active role in guiding the development of web standards (such as the markup languages in which web pages are composed), and 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 flexible format. It thus played an important role in popularizing use of the Internet.[27] Although the two terms are sometimes conflated in popular use, World Wide Web is not synonymous with Internet.[28] The web is a collection of documents and both client and server software using Internet protocols such as TCP/IP and HTTP.
Tim Berners-Lee was knighted in 2004 by Queen Elizabeth II for his contribution to the World Wide Web.
Function
The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not the same. The Internet is a global system of interconnected computer networks. In contrast, the web is one of the services that runs on the Internet. It is a collection of text documents and other resources, linked by hyperlinks and URLs, usually accessed by web browsers from web servers. In short, the web can be thought of as an application "running" on the Internet.[29]Viewing a web page on the World Wide Web normally begins either by typing the URL of the page into a web browser or by following a hyperlink to that page or resource. The web browser then initiates a series of communication messages, behind the scenes, in order to fetch and display it. In the 1990s, using a browser to view web pages—and to move from one web page to another through hyperlinks—came to be known as 'browsing,' 'web surfing,' or 'navigating the web'. Early studies of this new behavior investigated user patterns in using web browsers. One study, for example, found five user patterns: exploratory surfing, window surfing, evolved surfing, bounded navigation and targeted navigation.[30]
The following example demonstrates how a web browser works. Consider accessing a page with the URL http://example.org/wiki/World_Wide_Web.
First, the browser resolves the server-name portion of the URL (example.org) into an Internet Protocol address using the globally distributed database known as the Domain Name System (DNS); this lookup returns an IP address such as 208.80.152.2. The browser then requests the resource by sending an HTTP request across the Internet to the computer at that particular address. It makes the request to a particular application port in the underlying Internet Protocol Suite so that the computer receiving the request can distinguish an HTTP request from other network protocols it may be servicing such as e-mail delivery; the HTTP protocol normally uses port 80. The content of the HTTP request can be as simple as the two lines of text GET /wiki/World_Wide_Web HTTP/1.1 Host: example.org
The computer receiving the HTTP request delivers it to web server software listening for requests on port 80. If the web server can fulfill the request it sends an HTTP response back to the browser indicating success, which can be as simple as HTTP/1.0 200 OK Content-Type: text/html; charset=UTF-8 followed by the content of the requested page. The Hypertext Markup Language for a basic web page looks like <html> <head> <title>Example.org – The World Wide Web</title> </head> <body> <p>The World Wide Web, abbreviated as WWW and commonly known ...</p> </body> </html>
The web browser parses the HTML, interpreting the markup (<title>, <p> for paragraph, and such) that surrounds the words in order to draw the text on the screen.
Many web pages use HTML to reference the URLs of other resources such as images, other embedded media, scripts that affect page behavior, and Cascading Style Sheets that affect page layout. The browser will make additional HTTP requests to the web server for these other Internet media types. As it receives their content from the web server, the browser progressively renders the page onto the screen as specified by its HTML and these additional resources.
Linking
Most web pages contain hyperlinks to other related pages and perhaps to downloadable files, source documents, definitions and other web resources. In the underlying HTML, a hyperlink looks like <a href="http://example.org/wiki/Main_Page">Example.org, a free encyclopedia</a>
The hyperlink structure of the WWW is described by the webgraph: the nodes of the webgraph correspond to the web pages (or URLs) the directed edges between them to the hyperlinks.
Over time, many web resources pointed to by hyperlinks disappear, relocate, or are replaced with different content. This makes hyperlinks obsolete, a phenomenon referred to in some circles as link rot and the hyperlinks affected by it are often called dead links. The ephemeral nature of the Web has prompted many efforts to archive web sites. The Internet Archive, active since 1996, is the best known of such efforts.
Dynamic updates of web pages
Main article: Ajax (programming)
JavaScript is a scripting language that was initially developed in 1995 by Brendan Eich, then of Netscape, for use within web pages.[31] The standardised version is ECMAScript.[31] To make web pages more interactive, some web applications also use JavaScript techniques such as Ajax (asynchronous JavaScript and XML). Client-side script
is delivered with the page that can make additional HTTP requests to
the server, either in response to user actions such as mouse movements
or clicks, or based on lapsed time. The server's responses are used to
modify the current page rather than creating a new page with each
response, so the server needs only to provide limited, incremental
information. Multiple Ajax requests can be handled at the same time, and
users can interact with the page while data is being retrieved. Web
pages may also regularly poll the server to check whether new information is available.[32]WWW prefix
Many hostnames used for the World Wide Web begin with www because of the long-standing practice of naming Internet hosts (servers) according to the services they provide. The hostname for a web server is often www, in the same way that it may be ftp for an FTP server, and news or nntp for a USENET news server. These host names appear as Domain Name System or (DNS) subdomain names, as in www.example.com. The use of 'www' as a subdomain name is not required by any technical or policy standard and many web sites do not use it; indeed, the first ever web server was called nxoc01.cern.ch.[33] According to Paolo Palazzi,[34] who worked at CERN along with Tim Berners-Lee, the popular use of 'www' subdomain was accidental; the World Wide Web project page was intended to be published at www.cern.ch while info.cern.ch was intended to be the CERN home page, however the dns records were never switched, and the practice of prepending 'www' to an institution's website domain name was subsequently copied. Many established websites still use 'www', or they invent other subdomain names such as 'www2', 'secure', etc.[citation needed]. Many such web servers are set up so that both the domain root (e.g., example.com) and the www subdomain (e.g., www.example.com) refer to the same site; others require one form or the other, or they may map to different web sites.The use of a subdomain name is useful for load balancing incoming web traffic by creating a CNAME record that points to a cluster of web servers. Since, currently, only a subdomain can be used in a CNAME, the same result cannot be achieved by using the bare domain root.[citation needed]
When a user submits an incomplete domain name to a web browser in its address bar input field, some web browsers automatically try adding the prefix "www" to the beginning of it and possibly ".com", ".org" and ".net" at the end, depending on what might be missing. For example, entering 'microsoft' may be transformed to http://www.microsoft.com/ and 'openoffice' to http://www.openoffice.org. This feature started appearing in early versions of Mozilla Firefox, when it still had the working title 'Firebird' in early 2003, from an earlier practice in browsers such as Lynx.[35] It is reported that Microsoft was granted a US patent for the same idea in 2008, but only for mobile devices.[36]
In English, www is usually read as double-u double-u double-u.[citation needed] Some users pronounce it dub-dub-dub, particularly in New Zealand. Stephen Fry, in his "Podgrammes" series of podcasts, pronounces it wuh wuh wuh.[citation needed] The English writer Douglas Adams once quipped in The Independent on Sunday (1999): "The World Wide Web is the only thing I know of whose shortened form takes three times longer to say than what it's short for".[citation needed] In Mandarin Chinese, World Wide Web is commonly translated via a phono-semantic matching to wàn wéi wǎng (万维网), which satisfies www and literally means "myriad dimensional net",[37] a translation that very appropriately reflects the design concept and proliferation of the World Wide Web. Tim Berners-Lee's web-space states that World Wide Web is officially spelled as three separate words, each capitalised, with no intervening hyphens.[38]
Use of the www prefix is declining as Web 2.0 web applications seek to brand their domain names and make them easily pronounceable.[39] As the mobile web grows in popularity, services like Gmail.com, MySpace.com, Facebook.com and Twitter.com are most often discussed without adding www to the domain (or, indeed, the .com).
Scheme specifiers: http and https
The scheme specifier http:// or https:// at the start of a web URI refers to Hypertext Transfer Protocol or HTTP Secure respectively. Unlike www, which has no specific purpose, these specify the communication protocol to be used for the request and response. The HTTP protocol is fundamental to the operation of the World Wide Web and the added encryption layer in HTTPS is essential when confidential information such as passwords or banking information are to be exchanged over the public Internet. Web browsers usually prepend http:// to addresses too, if omitted.Web servers
Main article: Web server
The primary function of a web server is to deliver web pages on the
request to clients. This means delivery of HTML documents and any
additional content that may be included by a document, such as images,
style sheets and scripts.Privacy
Main article: Internet privacy
Every time a web page is requested from a web server the server can
identify, and usually it logs, the IP address from which the request
arrived. Equally, unless set not to do so, most web browsers record the
web pages that have been requested and viewed in a history feature, and usually cache
much of the content locally. Unless HTTPS encryption is used, web
requests and responses travel in plain text across the internet and they
can be viewed, recorded and cached by intermediate systems.When a web page asks for, and the user supplies, personally identifiable information such as their real name, address, e-mail address, etc., then a connection can be made between the current web traffic and that individual. If the website uses HTTP cookies, username and password authentication, or other tracking techniques, then it will be able to relate other web visits, before and after, to the identifiable information provided. In this way it is possible for a web-based organisation to develop and build a profile of the individual people who use its site or sites. It may be able to build a record for an individual that includes information about their leisure activities, their shopping interests, their profession, and other aspects of their demographic profile. These profiles are obviously of potential interest to marketeers, advertisers and others. Depending on the website's terms and conditions and the local laws that apply information from these profiles may be sold, shared, or passed to other organisations without the user being informed. For many ordinary people, this means little more than some unexpected e-mails in their in-box, or some uncannily relevant advertising on a future web page. For others, it can mean that time spent indulging an unusual interest can result in a deluge of further targeted marketing that may be unwelcome. Law enforcement, counter terrorism and espionage agencies can also identify, target and track individuals based on what appear to be their interests or proclivities on the web.
Social networking sites make a point of trying to get the user to truthfully expose their real names, interests and locations. This makes the social networking experience more realistic and therefore engaging for all their users. On the other hand, photographs uploaded and unguarded statements made will be identified to the individual, who may regret some decisions to publish these data. Employers, schools, parents and other relatives may be influenced by aspects of social networking profiles that the posting individual did not intend for these audiences. On-line bullies may make use of personal information to harass or stalk users. Modern social networking websites allow fine grained control of the privacy settings for each individual posting, but these can be complex and not easy to find or use, especially for beginners.[40]
Photographs and videos posted onto websites have caused particular problems, as they can add a person's face to an on-line profile. With modern and potential facial recognition technology, it may then be possible to relate that face with other, previously anonymous, images, events and scenarios that have been imaged elsewhere. Because of image caching, mirroring and copying, it is difficult to remove an image from the World Wide Web.
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