HTML and CSS

The previous section of the study came into contact with HTML and CSS this week.

First of all, it's a conceptual thing.

World Wide Web Consortium is currently the most authoritative and influential technology standards organization in the field, so far, more than 200 far-reaching web technology standards and implementation guides have been published.

WHATWG: Full Name: Web Hypertext Application Technology Working Group, Hypertext Application Technology Working Group

html full name: Hypertext Markup Language, Chinese is hypertext mark (Mark/element/tag) language. Used to define the document structure code written in this language is usually performed by the browser parsing

Hypertext hypertext: Including text, images, links, audio, video and other elements

Markup Language Markup Language: a set of tag tags that HTML uses to describe Web pages

CSS full name cascading style Sheets, Chinese: Cascading style sheet. Role: Used to define the style (appearance) of the HTML document, the basis of the page performance, you can control the layout, the rendering of elements.

HTML feels the structure of the document, CSS determines the style of the document

< Span class= "token p" > One: HTML term

< Span class= "token p" > html notes.    writing format: <!--notes->

HTML elements are an important part of an HTML document, with a large number of elements in an HTML document, and all content structures in the HTML are organized into pages by elements .

< Span class= "token p" > html element

< Span class= "token p" > sort for,< start tag > element content < end tag >,* Note: The end tag has a slash * < h3 > element content

< Span class= "token p" > expand: ** attribute written in start tag, example <a href ="/classroom/17 "> Join now </a > function: Additional functions. Here "href" is the property name * ""/CLASSROOM/17 "" is the attribute value (to be quoted), the start tag inside the property can be multiple.

< Span class= "token lf" > empty element (self-closing element): No element content and end tag, usually placed on start tag < img src= "XXXX" Alt> notation:< Tag name attribute > or < tag name attribute/>

< Span class= "token em" > -If a element directly contains B, then a is a parent of B (also called ancestor Element), B is a child element (descendant element). -If two elements have the same parent element, they are sibling elements.   if a directly or indirectly contains B, then a is the ancestor element of B, b is the descendant element of a.

Two: HTML document structure

Document declaration: Must be placed in the first line of the HTML document, not the element, but also have angle brackets, code format <! DOCTYPE Html>, which represents the version of HTML5 used

Role: Tell the browser is in which HTML version to parse the following code, if you do not write the document declaration, the browser renders the page may enter the strange mode

HTML element: also known as the root tag, the root element, which is the ancestor of all elements, all other elements of the document must be placed in its element content .

< Span class= "token em" >< Span class= "token MD md-strong" > related properties: lang (language)     This property specifies the natural language in which the text in the document is written, which may affect the browser's voice reading and translation behavior.

< Span class= "token em" >< Span class= "token MD md-strong" >head element: < Span class= "token MD md-strong" >** the first child element Note: The contents of the head element are not displayed on the page.

< Span class= "token em" >< Span class= "token MD md-strong" > head element typically contains  title   meta   

< Span class= "token em" >< Span class= "token MD md-strong" > title: Identifies the document title, which appears in the title bar of the browser or on the tab page.

< Span class= "token MD md-strong" > < Span class= "token MD md-strong" > meta: identifies other elements of the page (additional information about the page), which is a < Span class= "token MD md-strong" >** empty element **. Example: **< Meat charset= "UTF-8 ">** (translated into Chinese). : Instructs the browser to parse the page using the character encoding set UTF-8, which is usually located closest to the head.

role : In order to obtain better geographical compatibility, avoid garbled characters, the character encoding set should be set to UTF-8 and the code as the first child element of head

HTML and CSS