The difference between html and css

In front-end development, HTML and CSS are two basic programming languages. Among them, HTML is a hypertext markup language, which is used to define the content structure of a web page; CSS is a cascading style sheet, which is used to define the style expression of a web page. The functions of the two are different. This article will introduce and compare these two languages ​​and explain their differences.

1. The role of HTML

HTML is a hypertext markup language, used to define the content structure of web pages. For example, when a user visits a webpage, the webpage content defined by HTML will be displayed, so HTML is the skeleton of the webpage. HTML can define various tags, such as titles, paragraphs, lists, links, etc., and can set various styles and layout methods through nesting and attributes.

HTML only describes the content of the web page and does not involve its style. Therefore, when a web page only has HTML and no CSS, its rendering effect will be very primitive.

2. The role of CSS

CSS is a cascading style sheet, used to define the style expression of web pages. It can control the color, size, font, etc. of text, as well as the style of pictures and backgrounds, and can also make layout adjustments, such as setting the position and alignment of elements, etc.

CSS can be combined with HTML to display a beautiful web page. Although the HTML-only page has a clear purpose, it lacks sophisticated display effects. Web pages with CSS styles will have a better user experience.

3. The relationship between HTML and CSS

HTML and CSS are actually "separated", that is, HTML is used to describe content, and CSS is used to describe Style, the responsibilities of both are retained separately. Use HTML tags to distinguish the content structure of the page, and use CSS to control their style and presentation, thereby forming the overall presentation effect of the web page. The advantage of this "separation" is reflected in the reuse and style adjustment of HTML files. Styles can be managed uniformly through one CSS file without having to define them repeatedly in each file.

The relationship between HTML and CSS can also be described as a "waterfall model": at the upper level of the page, there is the document structure, layout and content of HTML, and below it is the cascading style sheet of CSS. When the browser parses a web page, it first reads the HTML document, then parses the style information and renders it on the web page.

4. Application fields of HTML and CSS

Normally, HTML and CSS are the basic components of developing websites and web pages. Whether you are developing a simple static web page or a dynamic interactive website, you need to use HTML and CSS. Compared with dynamic languages ​​(such as PHP, JavaScript, etc.), HTML and CSS are relatively stable languages, and users do not need to change versions frequently.

5. Summary

In front-end development, HTML and CSS are two essential programming languages. HTML is used to describe the content of a web page, and CSS is used to describe the style and presentation of a web page. Both languages ​​have their own application scenarios in web development. They are used to create various types of web pages, such as company websites, e-commerce websites, blogs, etc. During use, you need to follow the principle of separation between the two to improve the reusability and maintainability of the code.

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