Three forms: 1. Write the style in the style attribute of the tag, the syntax is "
"; 2. Write the style in the style tag pair, the syntax is "< ;style>code”; 3. Put the css code into the “.css” file and introduce it using the link tag.
The operating environment of this tutorial: Windows7 system, CSS3&&HTML5 version, Dell G3 computer.
1. Inline style
sets the style of the element through the style attribute of the tag. Its basic syntax format is as follows:
<element style="属性:值;属性:值;...">内容</element>
style in syntax It is an attribute of the tag. In fact, any HTML tag has the style attribute, which is used to set the inline style. The writing specification of the attribute value is the same as the CSS style rule. The inline style works on all its tags and the subtags nested in it. .
2. Internal style sheet
Embedded style is to write the css code in the head tag of the HTML document and define it with the style tag. Its basic The syntax format is as follows:
<head>
<style type="text/css">
css选择器{
属性:值;
属性:值;
}
</style>
</head>In syntax, the style tag is generally located after the head tag, and it can also be placed anywhere in the HTML document.
3. External link style
The linked style is to place all styles in one or more external style sheet files with CSS as the extension. The link tag links external styles to the HTML document. Its basic syntax format is as follows:
<link rel="stylesheet" type="text/css" href="css文件路径" />
| Attribute | Description |
|---|---|
| rel | Define the relationship between the current document and other linked documents. "stylesheet" means: the linked document is a style sheet file |
| href | Define the URL of the linked external style sheet file, which can be a relative path or an absolute path |
Advantages:
Complete separation of structure and performance code
Facilitates reuse and maintenance
Because Separating into separate files greatly reduces the size of HTML files, making the page structure easier to read by programmers and web crawlers
Friendly to search engines, making search engines Give the page a higher score, which is beneficial to the page's search engine ranking
The external style sheet is cached on the user's computer after the user's first visit, and does not need to be loaded on the next visit
Disadvantages:
If there are many styles, the CSS file will become very large and difficult to find. In addition, one more CSS file means one more HTTP request, which will increase the pressure on the server on a website with a large number of visits
(Learning video sharing: css video tutorial)
The above is the detailed content of What are the three main forms of using css on the page?. For more information, please follow other related articles on the PHP Chinese website!
Optimizing Performance with useState() in React ApplicationsApr 27, 2025 am 12:22 AMuseState()iscrucialforoptimizingReactappperformanceduetoitsimpactonre-rendersandupdates.Tooptimize:1)UseuseCallbacktomemoizefunctionsandpreventunnecessaryre-renders.2)EmployuseMemoforcachingexpensivecomputations.3)Breakstateintosmallervariablesformor
Sharing State Between Components Using Context and useState()Apr 27, 2025 am 12:19 AMUse Context and useState to share states because they simplify state management in large React applications. 1) Reduce propdrilling, 2) The code is clearer, 3) It is easier to manage global state. However, pay attention to performance overhead and debugging complexity. The rational use of Context and optimization technology can improve the efficiency and maintainability of the application.
The Impact of Incorrect Keys on React's Virtual DOM UpdatesApr 27, 2025 am 12:19 AMUsing incorrect keys can cause performance issues and unexpected behavior in React applications. 1) The key is a unique identifier of the list item, helping React update the virtual DOM efficiently. 2) Using the same or non-unique key will cause list items to be reordered and component states to be lost. 3) Using stable and unique identifiers as keys can optimize performance and avoid full re-rendering. 4) Use tools such as ESLint to verify the correctness of the key. Proper use of keys ensures efficient and reliable React applications.
Understanding Keys in React: Optimizing List RenderingApr 27, 2025 am 12:13 AMInReact,keysareessentialforoptimizinglistrenderingperformancebyhelpingReacttrackchangesinlistitems.1)KeysenableefficientDOMupdatesbyidentifyingadded,changed,orremoveditems.2)UsinguniqueidentifierslikedatabaseIDsaskeys,ratherthanindices,preventsissues
Common Mistakes to Avoid When Working with useState() in ReactApr 27, 2025 am 12:08 AMuseState is often misused in React. 1. Misunderstand the working mechanism of useState: the status will not be updated immediately after setState. 2. Error update status: SetState in function form should be used. 3. Overuse useState: Use props if necessary. 4. Ignore the dependency array of useEffect: the dependency array needs to be updated when the state changes. 5. Performance considerations: Batch updates to states and simplified state structures can improve performance. Correct understanding and use of useState can improve code efficiency and maintainability.
React's SEO-Friendly Nature: Improving Search Engine VisibilityApr 26, 2025 am 12:27 AMYes,ReactapplicationscanbeSEO-friendlywithproperstrategies.1)Useserver-siderendering(SSR)withtoolslikeNext.jstogeneratefullHTMLforindexing.2)Implementstaticsitegeneration(SSG)forcontent-heavysitestopre-renderpagesatbuildtime.3)Ensureuniquetitlesandme
React's Performance Bottlenecks: Identifying and Optimizing Slow ComponentsApr 26, 2025 am 12:25 AMReact performance bottlenecks are mainly caused by inefficient rendering, unnecessary re-rendering and calculation of component internal heavy weight. 1) Use ReactDevTools to locate slow components and apply React.memo optimization. 2) Optimize useEffect to ensure that it only runs when necessary. 3) Use useMemo and useCallback for memory processing. 4) Split the large component into small components. 5) For big data lists, use virtual scrolling technology to optimize rendering. Through these methods, the performance of React applications can be significantly improved.
Alternatives to React: Exploring Other JavaScript UI Libraries and FrameworksApr 26, 2025 am 12:24 AMSomeone might look for alternatives to React because of performance issues, learning curves, or exploring different UI development methods. 1) Vue.js is praised for its ease of integration and mild learning curve, suitable for small and large applications. 2) Angular is developed by Google and is suitable for large applications, with a powerful type system and dependency injection. 3) Svelte provides excellent performance and simplicity by compiling it into efficient JavaScript at build time, but its ecosystem is still growing. When choosing alternatives, they should be determined based on project needs, team experience and project size.
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
Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
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
Zend Studio 13.0.1
Powerful PHP integrated development environment
SublimeText3 Chinese version
Chinese version, very easy to use
Dreamweaver Mac version
Visual web development tools
