World wide web

from Wikipedia, the free encyclopedia
The historic WWW logo designed by Robert Cailliau
Graphic representation of some websites on the World Wide Web at en.wikipedia.org in July 2004
Visualization of the World Wide Web Common Crawl from 2012 (44 million domains)

The World Wide Web [ ˌwɜːldˌwaɪdˈwɛb ] ( listening ? / I ) ( English for "worldwide network", short Web , WWW , rarely and especially in the early days and the USA also W3 ) is a system of electronic hypertext that can be accessed via the Internet - Documents, so-called websites , which are described with HTML . They are by hyperlinks linked to each other and the Internet via the protocols HTTP or HTTPS transfer. The web pages mostly contain texts, often illustrated with pictures and graphic elements . Videos , audio documents or pieces of music are also often embedded. Audio file / audio sample

General

Colloquially, the World Wide Web is often equated with the Internet , but it is more recent and only represents one of several possible uses of the Internet. Other Internet services such as e-mail , IRC or SSH are not integrated into the World Wide Web .

To access content from the World Wide Web , a web browser is required, which z. B. runs on a PC or smartphone . With it, the user can download the data provided on any desired web server selected by him and display it on a suitable output device such as a screen or a Braille display. The user can then follow the hyperlinks on the displayed website, which refer to other websites , regardless of whether these are stored on the same web server or on a different one. This results in a worldwide network of websites. Following the hyperlinks is also known as “ surfing the Internet ”.

With the so-called Web 2.0 , websites became popular from around the 2000s, the content of which the user can not only view passively, as is the case with news sites, but also change and add to it himself, e.g. B. to publish your own content or to communicate with other users. These include blogs as private opinion pages, pages created by a loose community of authors based on the wiki principle and social networks such as forums . Server-side techniques and (script) languages ​​that implement this interactivity are mainly CGI , Python , ASP , Apache Wicket , JSF , ColdFusion , Ruby , PHP and SSI . To client-side techniques, e.g. For example, individualize the content using filters, including CSS , JavaScript or Java , where Java is mainly used for the platform-neutral execution of programs that are often loaded as web applications via the Internet and communicate with Internet-based databases (e.g. SAP clients) . With the interactivity, the use of search engines became possible, which supplemented the previously existing web directories and largely supplanted them to this day.

With the increasing complexity of formats, protocols and techniques, new job descriptions emerged, such as B. Web designer and media specialist . In addition to programming content, their tasks also include evaluating user behavior as part of log file analysis .

The WWW was developed in 1989 by Tim Berners-Lee and Robert Cailliau at the European research center CERN in Geneva , further developing known similar concepts . Berners-Lee developed the HTTP network protocol and the markup language HTML for this purpose . He also programmed the first web browser and the first web server software. He also ran the world's first web server on his NeXTcube development computer . The overall concept was made freely available to the public in 1991, renouncing any patenting or license payments , which contributed significantly to today's importance.

The world's first website info.cern.ch was published on August 6, 1991. A replica of this page can be reached via the following link:

The WWW led to extensive upheavals in many areas of life, often described as revolutionary, to the emergence of new branches of the economy and to a fundamental change in communication behavior and media use . In terms of its cultural significance, it is, along with other Internet services such as e-mail , partly equated with the invention of the printing press .

history

development

Robert Cailliau , Jean-François Abramatic and Tim Berners-Lee on the 10th anniversary of the World Wide Web Consortium
Tim Berners-Lee's first web server
Tim Berners-Lee, 2009

The web was created in 1989 as a project at the research institute CERN , located near Geneva on Swiss and French territory, on which Tim Berners-Lee set up a hypertext system. He first presented the idea for this on March 12, 1989 at the research facility. The concept was co-designed by the Belgian Robert Cailliau . The original aim of the system was to easily exchange research results with colleagues. One way of doing this was by “weaving together” scientific articles - that is, creating a web. In Berners-Lee's own words:

"The WorldWideWeb (W3) is a wide-area hypermedia information retrieval initiative aiming to give universal access to a large universe of documents."

"The World Wide Web is a large-scale hypermedia initiative for information gathering with the aim of providing general access to a large collection of documents."

- Tim Berners-Lee

The underlying concept of the hypertext stems from earlier developments such as Ted Nelson's Xanadu project , Vannevar Bush's “ memex ” machine idea, and the Note Code Project.

The World Wide Web differs from the hypertext systems of that time (Note Code, for example, used simple and readable syntax and semantic descriptors). The WWW only needs unidirectional links instead of bidirectional ones , which makes it possible to set a link to a resource without the owner having to intervene. In addition, the World Wide Web  - unlike other protocols such as HyperCard or Gopher  - is based on a free protocol , which made it possible to develop servers and clients without restrictions due to licenses. Tim Berners-Lee made the World Wide Web project publicly available worldwide on August 6, 1991 with a contribution to the newsgroup alt.hypertext .

Berners-Lee called the first web viewer that was more of a browser-editor hybrid simply " WorldWideWeb ". He had written it on a NeXT computer in the fall of 1990 . He later renamed it to "Nexus" to avoid confusion with the World Wide Web (with spaces). It could only display text back then, but later browsers like Pei Weis Viola (1992) added the ability to display graphics. Marc Andreessen from the NCSA published a browser called “ Mosaic for X ” in 1993 , which soon brought unprecedented popularity to the web and the entire Internet beyond the previous user groups and an explosive growth. Marc Andreessen founded the company "Mosaic Communications Corporation", later " Netscape Communication ". Modern browsers can now also display additional features such as dynamic content, music, animations and videos. On April 30, 1993 the board of directors of the European nuclear research center CERN released the World Wide Web free of charge to the public .

Surname

In Berners-Lee's first project proposal in March 1989, the Web was still mesh (English braid ). The name was quickly discarded because it is too reminiscent of mess (English disorder ). The following naming attempts Mine of Information ( english Information Mine ) or The Information Mine had since the abbreviations MOI (not last French I ) had to be self-centered and TIM. In addition, a mine was only partially a suitable image, since you can only get something out of it, whereas the web should both provide information and be filled with it.

Eventually, Berners-Lee settled on the Web and the World Wide Web (based on the expression World Wide Wireless, which was coined in the early 20th century for the then-emerging global radio communication), although colleagues warned him that the English and French language-breaking abbreviation WWW would jeopardize the success of the project. Web seemed particularly appropriate as an image as it is in mathematics a network of nodes ( english nodes called), each of which can be associated with each.

functionality

The WWW is based on three core standards:

The following standards were added later:

The World Wide Web Consortium (W3C), led today by Tim Berners-Lee, inventor of the WWW, and others develop the HTML and CSS standards; other standards come from the Internet Engineering Task Force , ECMA, and manufacturers such as Sun Microsystems . JavaScript , the most widely used script or macro language for web browsers, is not standardized by the W3 consortium .

JavaScript is a scripting language with instructions for the browser with which small programs (scripts) can be embedded. This allows Web pages using the Document Object Model s be changed dynamically (DOM). Scripts are usually small programs, but can also act as client managers with the help of the DOM and take full control of the display. A variant of JavaScript developed by Microsoft is called JScript . Both languages ​​are similar, but not compatible with each other. This incompatibility was a crucial part of what is known as the browser war .

The WWW was and is being supplemented by other technologies. Pictures were used for illustration very early on; the formats GIF were used for graphics and animations and JPEG for photos. Later, GIF was more and more superseded by PNG because - unlike GIF - there were no license fees for its use.

In addition, numerous other file types could be displayed in browsers using browser extensions, so-called plug-ins . This means that multimedia content from animations to music and videos or entire applications such as insurance calculators or navigation interfaces can be displayed. For example, Java applets made it possible to embed programs that run locally on the computer of the WWW user, and Flash was used for interactive content or animation.

With the introduction of HTML5 and other standardized techniques, plug-ins were quickly pushed out of the market, as the functions for animations and multimedia content etc. were now built directly into the browser and could therefore be implemented without external dependencies. For security and stability reasons, most of the larger browsers mostly deactivate large parts or the entire NPAPI interface that was used for these plug-ins . However, formats such as PDF for displaying documents are still popular , and most of them can now also be displayed by PDF readers built into the browser.

Dynamic websites and web applications

With the help of dynamic WWW pages, the WWW can serve as a surface for remote programs: A program is no longer started conventionally locally on the computer, but is viewed and operated via a web browser. The advantage here is that the programs are no longer distributed on the individual computers and have to be administered there (decentrally).

Dynamic web applications are executed either on the web server or directly in the browser.

  • Execution of web applications on the web server: The content is generated by web applications written in script languages ​​(such as PHP or Perl ) or compiled applications (such as JSP , servlets or ASP.NET ) and delivered to the browser.
  • Dynamic websites on the client: The browser creates or changes content using JavaScript.
  • Mixed version: Ajax is a mixed version - here the browser sends a request using JavaScript, which is processed by the web server and dynamically renews parts of the HTML structure.

The limited possibilities for expression on WWW pages are disadvantageous, so that programs in the form of Internet pages are generally not as easy to use as conventional programs. Rich Internet Applications are a trend that tries to reconcile the two .

At the moment it can be observed that more and more services, which were originally separated from the WWW and ran as a separate program, are offered via the WWW and can be used with a browser:

Thus Webmail often called e-mail client or WebFTP as FTP use client; Web forums replace the Usenet and Web chats the IRC .

Compatibility and Accessibility

Browser manufacturers often introduced new possibilities without waiting for standardization. Conversely, however, not all parts of standards such as HTML or CSS are implemented correctly. This leads to incompatibilities between certain websites and some browsers. At the beginning of the Internet boom, the company Netscape , today especially the company Microsoft with its Internet Explorer, “excelled” through such incompatibilities .

In addition, due to the multitude of ad hoc extensions to HTML, a major advantage of this language was lost - the separation of content and presentation. This separation allows the content marked in HTML to be optimally prepared for the respective output device. The range of output devices worthy of support extends from the high-resolution screen of a desktop computer , the small screen of a low-performance mobile phone, to black and white e-book readers with a low frame rate , to voice output using a screen reader and control using a Braille display for users with visual difficulties.

The W3C and other initiatives are therefore pushing the development in the direction of standardization and cross-browser unification of HTML / XHTML and CSS in order to regain these advantages of HTML. The increasing abandonment of plug-ins , such as Flash, also support this trend and have led to better accessibility . XHTML was later abandoned in favor of HTML5 , which also incorporated explicit features to improve accessibility and machine readability that are not visually visible.

See also

literature

Web links

Commons : World Wide Web  - collection of pictures, videos and audio files
Wikiversity: Course: Internet and Encryption / World Wide Web  - course materials

Individual evidence

  1. ↑ Internet and World Wide Web - the difference. News.de, October 29, 2009, accessed December 11, 2010 .
  2. ↑ WWW Proposal
  3. ↑ 25 years of the WWW: How three letters changed the world in Spiegel Online on August 5, 2016.
  4. ↑ Tilman Baumgärtel: Happy Birthday, WWW! Even a huge network begins with a single node at some point. The first website went online 25 years ago. In: taz.de. August 5, 2016. Retrieved August 6, 2016 .
  5. ↑ Proposal In: cern.ch.
  6. ↑ Patrick Beuth, Eike Kühl: 25 years of the World Wide Web. You've been growing a lot! Zeit Online , March 2, 2014. Retrieved January 15, 2017.
  7. ↑ 25 years ago: The WWW appeared on Usenet. In: heise online. Retrieved August 6, 2016 .
  8. ^ Tim Berners-Lee: WorldWideWeb - Executive Summary. In: groups.google.com , August 6, 1991.
  9. ↑ Detlef Borchers: 20 years ago: A proposal that is difficult to convey - and the beginning of the web. heise online, March 13, 2009, accessed on July 23, 2010 .
  10. ↑ Alexandra Budke / Detlef Kanwischer / Andreas Pott, Internetgeographien , 2004, p. 9.
  11. ^ Tim Berners-Lee: Information Management: A Proposal. CERN / W3C, March 1989, accessed on August 1, 2010 (English, see "Mesh" on the graphic).
  12. ↑ Simon Webb: The Analogue Revolution. Barnsley 2018, p. 167 f.
  13. ↑ Eric P. Wenaas: Radiola. The Golden Age of RCA 1919-1929. Chandler 2007, p. 32.
  14. ↑ Berners-Lee, Fischetti 2000, p. 23.
  15. ^ Dave Raggett, Arnaud Le Hors, Ian Jacobs: Introduction to HTML 4. What is the World Wide Web? In: HTML 4.01 Specification. World Wide Web Consortium, December 24, 1999, accessed February 16, 2019 .