What do the three W's in front of the website mean? And what do com and cn mean respectively?

The World Wide Web (also known as Web, WWW, W3, English Web or World Wide Web) is a data space. In this space: useful things are called "resources"; And is identified by a global uniform resource identifier (URL). These resources are transmitted to users through hypertext transfer protocol, and the latter obtains resources by clicking on links. From another point of view, the World Wide Web is a system that accesses tidal documents through the network. World Wide Web Consortium (W3C), also known as W3C Committee. 1994 10 was established in the computer science laboratory of Massachusetts Institute of Technology (MIT) with the title of "the best university in the world". The founder is Tim Berners Lee, the inventor of the World Wide Web.

The World Wide Web is usually regarded as a synonym for the Internet, but in fact it is a service running on the Internet.

[Edit this paragraph] Working principle

When you want to visit a webpage or other network resources on the World Wide Web, you usually need to type the uniform resource locator, abbreviated URL or link to the webpage or network resources through hyperlinks in the browser. After that, the server name part of the URL is first analyzed by the internet database called domain name system distributed all over the world, and which IP address to enter is determined according to the analysis results.

The next step is to send an HTTP request to the server working at the IP address to access the web page. In general, the HTML text, pictures and all other files that make up a web page will be requested one by one and sent back to the user soon.

The next job of the web browser is to show users the content described in HTML, CSS and other received files, plus images, links and other necessary resources. These constitute the "web page" you see.

[Edit this paragraph] Source

The earliest network idea of 200px-First_Web_Server.jpg can be traced back to the distant ENQUIRE project of Tim Berners-Li Jianzao in 1980. This is a hypertext online editing database similar to Wikipedia. Although this is very different from the World Wide Web we use now, they share many of the same core ideas, even including some ideas of the next project semantic web after Berners-Lee's World Wide Web.

1In March, 989, Berners-Li Zhuan wrote "Suggestions on Information Management", in which ENQUIRE was mentioned and a more complicated management model was described. 1990165438+1October 12 He put forward a more formal proposal about the World Wide Web in cooperation with robert cailliau. . 1990, 165438+ 10 month, 13, he wrote the first web page on the NeXT workstation to realize the ideas in his article.

During the Christmas holiday that year, Berners-Lee made all the tools needed for a network job [6]: the first World Wide Web browser (also an editor) and the first web server.

On August 6th, 199 1, he published an article about the World Wide Web project on the news group alt.hypertext. This day also marks the first appearance of World Wide Web services on the Internet.

Hypertext is an important concept in the World Wide Web, which originated from several projects in the 1960s. For example, Xanadu by Ted Nelson and NLS by douglas engelbart. The inspiration of these two projects comes from the memex system designed by Nivard Bush for microfilm in the paper "Think Like We Think" in 1945.

Another brilliant breakthrough of Tim Berners Lee is the grafting of hypertext onto the Internet. In his book "Weaving the Web", he explained that he had repeatedly suggested to the users of these two technologies that it was feasible to combine them, but no one responded to his suggestion, so he finally had to solve the scheme himself. He invented the unique authentication system of global network resources: uniform resource identifier.

There are many differences between the World Wide Web and other hypertext systems:

* The need for a single connection on the World Wide Web, rather than a two-way connection, allows anyone to link resources without any action by the resource owner. Compared with the early network system, this is very important to reduce the difficulty of realizing the network server and web browser, but its side effect is the stubborn disease of bad chain.

* Unlike some applications such as HyperCard, the World Wide Web is not proprietary, which enables servers and clients to develop and expand independently without licensing restrictions.

1On April 30th, 993, the European Organization for Nuclear Research announced that the World Wide Web was open to anyone free of charge. Two months later, Gopher announced that it was no longer free, causing a large number of users to switch from Gopher to the World Wide Web. World Wide Web Consortium (W3C), also known as W3C Committee. 1994 10 was established in the computer science laboratory of MIT. The founder is Tim Berners Lee, the inventor of the World Wide Web.

Since the 1940s, people have always dreamed of having a worldwide information base. In this database, data can not only be accessed by people all over the world, but also be easily linked to information in other places, so that users can obtain important information conveniently and quickly. It triggered the fifth information revolution.

With the rapid development of science and technology, this dream has become a reality. The most popular system used at present is called WWW. Its formal definition is "WWW is a wide-area hypermedia information retrieval initiative, which provides universal access to the world's documents." In short, WWW is an Internet-based computer network, which allows users to access information from one computer to another through the Internet. Technically speaking, the World Wide Web is a collection of clients and servers that support WWW protocol and Hypertext Transfer Protocol (HTTP) on the Internet. Through it, you can access hypermedia files all over the world, including words, graphics, sounds, animations, databases and various software.

Theoretically, the World Wide Web includes the whole Internet world of more than 200 million people, including all websites, gopher information stations, FTP files, Telnet public access accounts, news discussion forums and Wais databases. Therefore, the World Wide Web can be said to be the largest electronic information world in the world today, and the World Wide Web can be regarded as synonymous with the Internet. In fact, what we usually call "surfing the Internet" actually refers to connecting to the World Wide Web. WWW is the abbreviation of World Wide Web, and it can also be abbreviated as Web, and its Chinese name is World Wide Web.

[Edit this paragraph] Social impact

Because WWW provides people all over the world with the means to find and enjoy information, it can also be regarded as a collection of information that various organizations, scientific research institutions, universities and companies in the world are keen on research and development. It is based on Internet query. Information publishing and management system is a dynamic multimedia communication format for people to interact. Its formal expression is: "the original protocol of wide-area hypermedia information retrieval, the purpose of which is to access massive documents." What WWW has achieved is to provide a compatible means for users on the computer network to access various media in a simple way. It is the first truly global hypermedia network, which has changed the way people observe and create information. As a result, the research, development and use of WWW have quickly set off a huge upsurge all over the world.

WWW was born in the Internet and later became a part of it. Today, the World Wide Web is almost synonymous with the Internet. Through it, everyone who joins it can reach every corner of the world in an instant, just plug in a telephone line (maybe your laptop or your mobile phone) on your PC, and the global information is at your fingertips!

WWW doesn't actually exist anywhere in the world. In fact, users of WWW give it new meanings every day. In the Internet society, citizens (including institutions and individuals) embed all kinds of information they need to disclose into the WWW in the form of homepages, which include graphics, sounds and other media besides words. From all kinds of job advertisements to electronic bibles, it can be said that it is all-encompassing and ubiquitous. The homepage is published on the Web, mainly in the form of some HTML text (HTML is Hypertext Markup Language).

With the rapid development of mobile Internet access, some experts recently called it WAP and WWW. WAP has become a global de facto standard for accessing wireless information services through mobile phones or other wireless terminals. Its development and application are infinite.

[Edit the composition of this paragraph ]WWW

Master-slave network

A client is a program that needs something, while a server is a program that provides something. A client can request from many different servers. Servers can also provide services to many different clients. Usually, the client starts a conversation with the server. Servers are usually automated programs that wait for requests from clients. The client usually runs as a request from the user or from every program similar to the user. A protocol is a definition of various methods for a client to request a server and how the server responds to the request. WWW client can also be called browser.

The usual clients on the World Wide Web mainly include IE, Firefox, safia, opera and so on.

In the Web, the client's task is:

1. Helps you make a request (usually launched when you click the link point).

2. Send your request to the server.

3. Report the requested results to you by correctly decoding the direct image, submitting the HTML document and transferring various files to the corresponding "viewer".

Viewer is a program that can be called by WWW clients to present specific types of files. When a sound file is viewed and downloaded by your WWW client, it can only be "observed" by some programs (such as "media player" under Windows).

Generally speaking, WWW clients can make requests not only to Web servers, but also to other servers (such as Gopher, FTP, news and mail).

Computer network server

1. Accept the request

2. Check the legality of the request, including security screening.

3. Obtain and make data according to the request, including Java scripts and programs, CGI scripts and programs, set appropriate MIME types for files, and pre-process and post-process the data.

4. Send the information to the requesting client.