Today I open a cycle of lessons, with the help of which we will master the language HTML step by step. Of course, after reading this course, you will not immediately be a professional typesetter, you will still have to work for it. But it will give you the necessary theory, without which it is impossible to become a competent specialist. In today’s introductory lesson, we will get acquainted with the history of the emergence of the Internet, the basics of its functioning, as well as basic concepts. Next, let’s look at what is the markup language HTML and XHTML and their standards. At the end, we will get acquainted in detail with such a concept as the browser and its variations.
What is the Internet
Like many other inventions, the Internet came into being as a solution to some original problem. Initially, the task arose of merging several local computer networks into one common network in order to make it possible to exchange files between them. In other words, it was necessary to create a network of several other networks. These initial networks were located in completely different places, at a considerable distance from each other, and therefore all the methods of information transmission available at that time did not allow to effectively cope with the task.
How did it end up being implemented? At first, the staff of the ARPA (Advanced Research Projects Agency) Department of Defense of the USA developed ARPAnet somewhere in 1969 – one of the world’s first global networks, the forerunner of the Internet. IP (Internet Protocol) was developed to manage this network, allowing individual computers to communicate with each other.
IP (Internet Protocol) – A network layer protocol, which is a set of fixed rules, the combination of which allows different computers to interact with each other, regardless of which operating system they run. Thanks to him, it was possible to send communication packets along alternative routes in case of failure of one of the existing routes.
Thanks to the emergence of this protocol and the new global network (consisting of other computer networks), the task of exchanging information has become more accessible than ever before, but the process of exchanging data was still quite complicated. To find any specific information on the Internet, it was necessary to know exactly where it was saved. First of all, it was necessary to understand exactly how individual computers are interconnected, and, with this information, it was possible to navigate through the network to the data that interests you.
The situation changed in the early 1990s with the advent of a new network protocol. This protocol, called HTTP (Hypertext Transfer Protocol), allowed any user connected to the Internet to access any information, regardless of its location on the network. It is this one that allows you to go from one Web page to another simply by clicking on the appropriate link.
The advent of HTTP was a revolutionary event, but the codes that form it cannot independently provide a full cycle of information exchange. Data stored on networked computers (such as documents or other files) must include their own set of communication tools so that other computers can interpret them correctly. In the case of the World Wide Web, this tool is HTML.
What is HTML?
HTML is a hypertext markup language. Most of the documents displayed on the world wide web are written in HTML. This language allows you to specify how text, images, sound files, video files or electronic information of almost any other type can be displayed on Web pages. Using this language, you can format documents and associate them with each other, regardless of the type of computers on which these documents were originally created.
Why is this circumstance so important? For example, if you created a document in your favorite word processor and sent it to another user on whose computer the same word processor is not installed, it will not be able to open and read the document you sent, will it? The same can be said about virtually any other type of file (including spreadsheets, databases, or accounting files).
Instead of using its own unique codes that can only be interpreted by the appropriate software, HTML captures its instructions in plain text, which can be correctly interpreted by any Web browser or word processor. These programs identify individual specific elements of the document (such as the header, body of the page, or footer) and, on the basis of this information, determine the features of the display of certain components of the page.
These specific elements are called tags. They are promoted to determine how the web page is presented. They are almost always used in pairs, surrounding the designated component. The tags are developed by the W3C (World Wide Web Consortium) consortium, which develops and promotes uniform standards and protocols that enhance the functionality of the world wide web. Currently, more than 180 commercial, educational and government organizations are members of this consortium.
What is XHTML
XHTML – stands for extensible hypertext markup language. It is a modernized version of HTML. XML – Abbreviation for Extensible Markup Language — Extensible Markup Language. Designed by the W3C consortium, this World Wide Web document formatting language is more flexible and functional.
The advent of the XHTML specification was the result of the first significant modification of the HTML language. Changes were made to add to the HTML pages structured and extensible language XML. By adding a few simple structural elements to existing HTML pages, you can be sure that your Web pages will be compatible with later versions of HTML and even with XML.
Thus, the following provisions apply to the XHTML standards: each tag must be explicitly closed either with a corresponding closing tag or with a slash at the end of the tag (in the absence of a closing tag); each tag must be in lower case letters; tag attributes are quoted; each tag attribute must have a value.
What is a browser
A browser is a program designed for browsing the web. The first browser Mosaic appeared in 1993. Over time, other browsers have been created, the list of which is currently very extensive and diverse. Each browser has its own unique features, so in order to test the universality of the code, it is required to view and correct the code with their account. To date, the most relevant Firefox, Chrome, Opera and Internet Explorer and Safari.
A web browser is installed on your computer. When you search for some information on the world wide web, your browser must find the place where this information is stored. It solves this problem using the HTTP protocol. Then the server on which the information you are interested in is sent to your computer the corresponding Web page (as a plain text file) using the same HTTP protocol.
Your Web browser sees the new Web page and displays its captions and graphics with all the formatting features, interpreting the text and HTML tags. HTTP is not the only protocol used on the Internet. For various network services, such as e-mail or file distribution, proprietary data transfer protocols are provided.
In all subsequent lessons, you will find recommendations on how to ensure the correct reproduction of Web pages that meets your requirements. Stick to these recommendations, creating your own Web pages, and you will avoid unpleasant situations when, having spent a lot of time and effort on developing a page design, you suddenly find that it looks completely different on any other computer or in a window of some kind another browser.
According to the materials of the book Didra Haze ” Learn your own HTML “.