1. Что такое фронт енд.
	- клиент серверная коммуникация;
	-
2. Что такое веб страница:
	Веб страница состоит из трех слоев:
	1. The three layers
		A Web page consists of three layers (and yes, these are the ones that need to be separated fromeach other):
	1. HTML structure.
	2. CSS presentation.
	3. JavaScript behavior.
The HTML structural layer is the most basic part of the page. The HTML tags form the structure of the
page and give meaning to its content. For instance, if a certain text is marked up with an <h1>, it's a
header and should be treated as such. Browsers (or, more generally, user agentsprograms that
interpret HTML) are expected to distinguish this header from the surrounding normal text, for
instance by displaying it in bold and in a larger font, or by pronouncing it louder or slower. Once
you've created structurally correct HTML, you can be reasonably certain that most user agents,
hence most users, will recognize a header as a header.
The purpose of the CSS presentation layer is to define how your HTML should be presented. CSS
allows you to specify colors, fonts, leading, and other typographical elements, as well as the general
layout of the page, for instance, "The navigation block goes next to the content block."
The JavaScript behavior layer adds interactivity to an HTML/CSS page. As soon as you want
something to happen when the user mouses over an HTML element, you need JavaScript to
implement the effect.
Every Web page needs an HTML structural layerwithout HTML, there is no Web page. However, the
CSS and JavaScript layers are optional. Old, obscure, or unusual browsers may not support CSS
and/or JavaScript, in which case one or both layers may go missingthe presentation or behavior
instructions are never executed.