How javascript calls css
In web design and development, JavaScript and CSS are used together to achieve a variety of stunning visual effects and interactive features. How JavaScript calls CSS is a common question, which will be described in detail below.
1. Inline style
Inline style can be directly applied to the style attribute of the HTML tag, as shown below:
<p style="color: red; font-size: 16px;">这是一个红色的段落</p>
In JavaScript, you can change the element by style attribute to modify the inline style. For example:
let p = document.querySelector("p");
p.style.color = "blue";
p.style.fontSize = "20px";This will turn the red paragraph above into a blue paragraph with a font size of 20px.
2. External style sheets
An external style sheet is a method of placing a collection of CSS rules in a separate file. By associating the file with an HTML document, the same one can be reused Style rules. In JavaScript, a style sheet can be modified by changing the href attribute of the element in the document that is linked to the style sheet. For example:
<link rel="stylesheet" href="styles.css">
let link = document.querySelector("link");
link.href = "new-styles.css";This changes the stylesheet in the document that is linked to styles.css to a stylesheet that is linked to new-styles.css.
3. Internal style sheet
The internal style sheet is a method of placing a collection of CSS rules between the head or body tags of an HTML document. In JavaScript, internal style sheets can be modified by directly modifying the document's style attribute. For example:
<head>
<style>
p {
color: red;
font-size: 16px;
}
</style>
</head>
<body>
<p>这是一个红色的段落</p>
</body>let style = document.querySelector("style");
style.innerHTML = "p { color: blue; font-size: 20px; }";This will turn the red paragraph above into a blue paragraph with a font size of 20px.
4. Class name
The class name is a name that defines the style rules of certain elements. In JavaScript, one or more classes can be added or removed by modifying the classList attribute of an element. For example:
<style>
.red {
color: red;
}
.large {
font-size: 20px;
}
</style>
<p class="red">这是一个红色的段落</p>let p = document.querySelector("p");
p.classList.add("large");
p.classList.remove("red");This will turn the red paragraph above into a paragraph with a font size of 20px.
Summary:
JavaScript can use a variety of methods to call CSS, including inline styles, external style sheets, internal style sheets, and class names. These methods can directly operate the Document Object Model (DOM) through JavaScript to achieve visual effects and interactive functions. Mastering these skills can help you better manage and control the style and behavior of Web pages.
The above is the detailed content of How javascript calls css. For more information, please follow other related articles on the PHP Chinese website!
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
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
React's Role in HTML: Enhancing User Experience
Apr 09, 2025 am 12:11 AM
React 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.
React and the Frontend: Building Interactive Experiences
Apr 11, 2025 am 12:02 AM
React 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 Components: Creating Reusable Elements in HTML
Apr 08, 2025 pm 05:53 PM
React components can be defined by functions or classes, encapsulating UI logic and accepting input data through props. 1) Define components: Use functions or classes to return React elements. 2) Rendering component: React calls render method or executes function component. 3) Multiplexing components: pass data through props to build a complex UI. The lifecycle approach of components allows logic to be executed at different stages, improving development efficiency and code maintainability.
React and the Frontend Stack: The Tools and Technologies
Apr 10, 2025 am 09:34 AM
React 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 Ecosystem: Libraries, Tools, and Best Practices
Apr 18, 2025 am 12:23 AM
The React ecosystem includes state management libraries (such as Redux), routing libraries (such as ReactRouter), UI component libraries (such as Material-UI), testing tools (such as Jest), and building tools (such as Webpack). These tools work together to help developers develop and maintain applications efficiently, improve code quality and development efficiency.
Frontend Development with React: Advantages and Techniques
Apr 17, 2025 am 12:25 AM
The advantages of React are its flexibility and efficiency, which are reflected in: 1) Component-based design improves code reusability; 2) Virtual DOM technology optimizes performance, especially when handling large amounts of data updates; 3) The rich ecosystem provides a large number of third-party libraries and tools. By understanding how React works and uses examples, you can master its core concepts and best practices to build an efficient, maintainable user interface.
React vs. Backend Frameworks: A Comparison
Apr 13, 2025 am 12:06 AM
React 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.
Understanding React's Primary Function: The Frontend Perspective
Apr 18, 2025 am 12:15 AM
React's main functions include componentized thinking, state management and virtual DOM. 1) The idea of componentization allows splitting the UI into reusable parts to improve code readability and maintainability. 2) State management manages dynamic data through state and props, and changes trigger UI updates. 3) Virtual DOM optimization performance, update the UI through the calculation of the minimum operation of DOM replica in memory.
