www World Wide Web and the story of HTML

Describing the diagram between the World Wide Web and HTML, let me give you a detailed description of their family.

Www:

WWW is the abbreviation of Global Information Network (World Wide Web), it also has a nickname, such as the Web, W3, Chinese called the World Wide web. Divided into Web clients and Web server programs. WWW allows Web clients (popular browsers) to access pages on a browser Web server, a system made up of many interconnected hypertext links, accessed over the Internet. In this system, each useful thing, called a "resource," is identified by a global Uniform Resource Identifier (Uri:uniform Resource Identifier), which passes through the Hypertext Transfer Protocol (Hypertext Transfer Protocol) is delivered to the user, and the user clicks on the link to get the resource.

The World Wide Web is not the same as the Internet, and the World Wide Web is just one of the services that the Internet can provide, a service that runs on the Internet.

Hypertext:

Hypertext is a program called Web browser (browser), is to put some information according to the need to connect information management technology, people can use a text link pointer to open another related text. You can get relevant information by simply clicking on an entry that is usually underlined in the text with your mouse. The Web browser retrieves information called "document" or " Web page " from the Web server and displays it. Usually displayed on a computer monitor, people can retrieve files with hyperlinks (Hyperlink) on the Web page, or even send data to the server, along with the behavior of hyperlinks to browse the Web . The relevant data is usually lined up as a group of pages , also called sites . Web page is the basic information unit of the site, is the basic document of the WWW, he is composed of text, pictures, animation, sound and other media information and links, is written in HTML , with the extension of. html and. htm, and links to other Web pages or Web sites to connect and jump.

Hypertext Markup Language

HTML (hypertext Markup Language). It is the next application of the Standard Universal Markup Language . The role of Hypertext Markup language is to define the structure and format of hypertext documents. is also a norm, a standard. It marks each part of the Web page you want to display with a marker symbol. The Web page file itself is a text file, by adding a marker in a text file, you can tell the browser how to display the content (such as: How the text is handled, how the picture is arranged, how the image is displayed, etc.). The browser reads the Web page file sequentially, and then interprets and displays the contents of its tag according to the marker, and the mark that writes the error does not indicate its error, and does not stop its interpretation execution, the author can only display the effect to analyze the cause of the error and the error site. It is important to note, however, that for different browsers, there may be different interpretations of the same marker, which may result in differing displays.

HTTP protocol

HTTP is the abbreviation for Hypertext Transfer Protocol, the Hypertext Transfer Protocol. HTTP provides the ability to access hypertext information, which is an application-level communication protocol between the WWW browser and the WWW server. The HTTP protocol is a universal, object-oriented protocol for distributed and collaborative hypertext information Systems. By extending the command, it can be used for similar tasks, such as domain name services or distributed object-oriented systems. WWW uses the HTTP protocol to transmit various hypertext pages and data.

The HTTP protocol session process consists of 4 steps.
(1) Establish a connection: the client's browser sends a request to the server to establish a connection, and the service side gives a response to establish a connection.
(2) Sending a request: The client sends its own request to the server through the connection as required by the Protocol.
(3) Give answer: the server responds to the client's request and returns the result (HTML file) to the client.
(4) Close connection: The client closes the connection after receiving an answer.

The HTTP protocol is a protocol based on TCP/IP that not only guarantees the proper transmission of hypertext documents, but also determines which part of the document is being transmitted, and which content is displayed first (such as text before graphics). HTTP transmits the user's data, including the user name and password, in plaintext, has security implications, is susceptible to theft, and can use HTTPSwith confidential functionality for transmission of sensitive data (secure hypertext Transfer PROTOCOL) protocol.

FTP protocol

File Transfer Protocol (FTP) is a protocol used on the Internet to access remote machines, which enables users to operate on files between local and remote machines. The FTP protocol allows you to transfer arbitrary files and allow files to have ownership and access rights. In other words, the FTP protocol can be used to upload or download files to and from the FTP server on the Internet.
Like other Internet apps, FTP also uses client/server mode, which includes client FTP and server FTP, client FTP initiates the transfer process, and server FTP responds to it. There are some websites on the internet that provide services in accordance with the FTP protocol, allowing users to access files, which are FTP servers. Users on the Internet to connect to the FTP server, is to use the FTP client software. Usually windows has an FTP command, which is actually a command line FTP client program, in addition to the Common FTP client program cuteftp, LEAPFTP, FLASHFXP and so on.

These are a brief introduction to the WWW-related concepts, and the stories of him and HTML can be found in the mind map.

Finally, introduce the user to browse the principle of the page, the direct view of the picture. A picture is worth thousands of thousand words:

www World Wide Web and the story of HTML