What is the difference between css and javascript

CSS and JS are two important technical aspects in modern web design and development. Both have different roles and uses, but there are differences between the two that many people may not understand. In this article, we will introduce and compare CSS and JS in detail, and explain the differences between them.

CSS: Cascading Style Sheets

CSS is a markup language used to control the style of web pages. It allows specifying appearance for specific HTML elements such as font, background color, border size, padding, position and layout, etc. Unlike HTML, the CSS language does not include markup or specific content, but focuses primarily on the appearance and formatting of the content. The advantage of CSS is that it can simplify the structure of HTML, making HTML files clearer, more concise, and easier to maintain and modify. CSS also plays a vital role in developing responsive, portable, accessible and usability-friendly websites.

Using CSS, you can control the appearance of page elements by:

• Specify the font type, size and color of text, links, and titles, etc.
• Adjust image size, position, frame, etc.
• Control the borders, padding, spacing and border type on the page.
• Define page background color and background image, etc.
• Design layout and typography and responsive design in the page.

Some advantages of CSS also include:

• Reusability: Developers can control the appearance and layout of the entire site using a single CSS file.
• Easy to modify: Modifying the CSS file alone can change the style and style of the entire site without refactoring the HTML code.
• Maintainability: The clarity and structure of CSS code simplifies tasks and workflows in web design and development.
• Readability: CSS has good readability and maintainability.

JS: JavaScript

JavaScript is a dynamically typed programming language used to add interactivity to web pages. JavaScript brings many amazing features to web development, such as validating form data, enabling user interaction, manipulating DOM objects, etc. JavaScript also provides external library, language, and framework support for cross-platform applications, game development, server-side programming, and mobile application development.

Some advantages of JavaScript also include:

• Interactivity: JavaScript continuously updates and changes various elements in the web page by processing user events such as mouse clicks, mouse movements, and even keyboard input. state.
• Responsiveness: JavaScript responds to user interaction. In addition to changing the state of the web page, it can also dynamically load new content, implement asynchronous operations, handle browser errors and exceptions, and perform back-end server request and response operations.
• Dynamics: JavaScript supports operations such as creating objects, function operations, and dynamically generating HTML. These features make the code easily adaptable to different situations and needs.
• Cross-browser compatibility: JavaScript is widely supported in almost all modern browsers.

The difference between CSS and JS:

1. CSS and JS have different uses

CSS is used to control the appearance and style of the website, while JS is used to provide Add interactivity features.

2. CSS priority display

The style information of the CSS page is executed first during the redrawing process of the page. So first you need to load CSS styles to ensure the visibility of the page, and modify and build the DOM structure. JavaScript code needs to be executed when the page is rendered.

3. Simple CSS processing

CSS is a type of text style processing that can render page-related visual modifications and layout layouts very quickly.

4.JS file size problem

JS files are often large because they must contain many functions and libraries to achieve specified tasks. This will result in slow page loading and performance bottlenecks.

Summary:

CSS and JS are both indispensable website development technologies. Although the purpose and role of the two are different, they both provide critical support for achieving the goals of the website. The advantages and features of both also enable web designers and developers to create rich, efficient and dynamic sites and achieve excellent user experience. For developers, when choosing CSS or JS, they must understand the functions, advantages and disadvantages of their implementation, and make correct choices and adjustments according to the needs of the target site.

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