The three components of a css style sheet: 1. Selector, used to tell the browser which objects in the page the specified style will act on; 2. Properties, which are set style options provided by CSS, mainly Including font attributes, text attributes, background attributes, layout attributes, etc.; 3. Attribute value is the valid value of the specified attribute, and the attribute and attribute value are separated by ":".

Composition of css style sheet
The CSS style sheet includes three parts: selectors, attributes and attribute values. The syntax style is as follows:选择符{属性:属性值;} The syntax description is as follows:
- Selector (Selector): also known as selector, is a very important concept in CSS, all in HTML Markers are controlled through different CSS selectors. It tells the browser which objects in the page the style will act on. These objects can be a certain tag, all web page objects, specified class or id values, etc. When the browser parses this style, it renders the display effect of the object based on the selector.
- Property: It is a set style option provided by CSS, mainly including font attributes, text attributes, background attributes, layout attributes, border attributes, list item attributes, and table attributes. etc. content. Some of these properties are only supported by some browsers, so their use becomes more complicated using CSS properties.
- Attribute value (value): The valid value of the specified attribute. Attributes and attribute values are separated by ":". When there are multiple attribute values, use ";" to separate them.

1. Tag selector
HTML page is composed of many tags, such as image tags
, hyperlink tag , table tag
The above is the detailed content of What three parts does a css style sheet consist of?. For more information, please follow other related articles on the PHP Chinese website!
React Inside HTML: Integrating JavaScript for Dynamic Web PagesApr 16, 2025 am 12:06 AMTo integrate React into HTML, follow these steps: 1. Introduce React and ReactDOM in HTML files. 2. Define a React component. 3. Render the component into HTML elements using ReactDOM. Through these steps, static HTML pages can be transformed into dynamic, interactive experiences.
The Benefits of React: Performance, Reusability, and MoreApr 15, 2025 am 12:05 AMReact’s popularity includes its performance optimization, component reuse and a rich ecosystem. 1. Performance optimization achieves efficient updates through virtual DOM and diffing mechanisms. 2. Component Reuse Reduces duplicate code by reusable components. 3. Rich ecosystem and one-way data flow enhance the development experience.
React: Creating Dynamic and Interactive User InterfacesApr 14, 2025 am 12:08 AMReact is the tool of choice for building dynamic and interactive user interfaces. 1) Componentization and JSX make UI splitting and reusing simple. 2) State management is implemented through the useState hook to trigger UI updates. 3) The event processing mechanism responds to user interaction and improves user experience.
React vs. Backend Frameworks: A ComparisonApr 13, 2025 am 12:06 AMReact is a front-end framework for building user interfaces; a back-end framework is used to build server-side applications. React provides componentized and efficient UI updates, and the backend framework provides a complete backend service solution. When choosing a technology stack, project requirements, team skills, and scalability should be considered.
HTML and React: The Relationship Between Markup and ComponentsApr 12, 2025 am 12:03 AMThe relationship between HTML and React is the core of front-end development, and they jointly build the user interface of modern web applications. 1) HTML defines the content structure and semantics, and React builds a dynamic interface through componentization. 2) React components use JSX syntax to embed HTML to achieve intelligent rendering. 3) Component life cycle manages HTML rendering and updates dynamically according to state and attributes. 4) Use components to optimize HTML structure and improve maintainability. 5) Performance optimization includes avoiding unnecessary rendering, using key attributes, and keeping the component single responsibility.
React and the Frontend: Building Interactive ExperiencesApr 11, 2025 am 12:02 AMReact is the preferred tool for building interactive front-end experiences. 1) React simplifies UI development through componentization and virtual DOM. 2) Components are divided into function components and class components. Function components are simpler and class components provide more life cycle methods. 3) The working principle of React relies on virtual DOM and reconciliation algorithm to improve performance. 4) State management uses useState or this.state, and life cycle methods such as componentDidMount are used for specific logic. 5) Basic usage includes creating components and managing state, and advanced usage involves custom hooks and performance optimization. 6) Common errors include improper status updates and performance issues, debugging skills include using ReactDevTools and Excellent
React and the Frontend Stack: The Tools and TechnologiesApr 10, 2025 am 09:34 AMReact is a JavaScript library for building user interfaces, with its core components and state management. 1) Simplify UI development through componentization and state management. 2) The working principle includes reconciliation and rendering, and optimization can be implemented through React.memo and useMemo. 3) The basic usage is to create and render components, and the advanced usage includes using Hooks and ContextAPI. 4) Common errors such as improper status update, you can use ReactDevTools to debug. 5) Performance optimization includes using React.memo, virtualization lists and CodeSplitting, and keeping code readable and maintainable is best practice.
React's Role in HTML: Enhancing User ExperienceApr 09, 2025 am 12:11 AMReact combines JSX and HTML to improve user experience. 1) JSX embeds HTML to make development more intuitive. 2) The virtual DOM mechanism optimizes performance and reduces DOM operations. 3) Component-based management UI to improve maintainability. 4) State management and event processing enhance interactivity.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Dreamweaver Mac version
Visual web development tools

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

SublimeText3 English version
Recommended: Win version, supports code prompts!

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),








