In modern web development, JavaScript (JS for short) has become an indispensable part. JS can not only achieve dynamic effects on web pages, but also facilitate code modularization and reuse through external JavaScript files. This article explains how to use external JavaScript files and the benefits of using external JavaScript files.
First, we need to understand what an external JavaScript file is. External JavaScript files refer to saving JS code in a separate JavaScript file and introducing it in HTML through the <script></script> tag. External JS files have separate file paths and file names, and references can be shared across multiple HTML pages.
Next, let’s take a look at how to use external JavaScript files.
Step 1: Create an external JavaScript file
To use an external JavaScript file, you need to create an independent .js file first. You can create files through any editor, such as Notepad or Sublime Text. Write your JS code in a file and save the file as a standalone JS file, such as myscript.js.
Step 2: Introduce external JavaScript files into HTML
To introduce external JavaScript files into HTML files, you need to use the <script></script> tag. There are two attributes in the tag: src and type. The src attribute is used to specify the path of the JS file, and the type attribute is used to specify the type of the JS file, usually set to text/javascript. The following is a code example that introduces an external JavaScript file:
<!DOCTYPE html> <html> <head> <script src="myscript.js" type="text/javascript"></script> </head> <body> </body> </html>
The above code will introduce an external file named myscript.js in the tag of HTML JavaScript files. In this way, when the HTML is loaded, the JS file will also be loaded and the code in it will be executed.
Benefit Analysis: Benefits of Using External JavaScript Files
Now, let’s take a look at the benefits of using external JavaScript files.
- Improve code maintainability
Separating JS code into independent files can make the code more structured and easier to maintain. If you want to modify the code, you only need to modify a separate file instead of modifying the code in each HTML file. - Facilitates code reuse
If you have multiple HTML files that need to use the same JS code, then using external JavaScript files can easily achieve code reuse. Just introduce the same JS file in different HTML files. - Reduce the loading time of the code
Using external JS files can reduce the size of the HTML file, thereby reducing the loading time of the page. Because JS files can be cached, if multiple HTML pages reference the same JS file, then when the first page loads the JS file, it will already be cached, so that the file will not be downloaded again on subsequent page loads.
Summary
In this article, we learned how to use external JavaScript files and the benefits of using external JavaScript files. For larger projects, using external JavaScript files can make the code more structured, easier to maintain and reuse, and can also help reduce page load times. Therefore, it is necessary to use external JavaScript files in the project. It is recommended that you modularize the JavaScript code as much as possible to better manage and maintain the code.
The above is the detailed content of How to use external javascript files. For more information, please follow other related articles on the PHP Chinese website!
The Size of React's Ecosystem: Navigating a Complex LandscapeApr 28, 2025 am 12:21 AMTonavigateReact'scomplexecosystemeffectively,understandthetoolsandlibraries,recognizetheirstrengthsandweaknesses,andintegratethemtoenhancedevelopment.StartwithcoreReactconceptsanduseState,thengraduallyintroducemorecomplexsolutionslikeReduxorMobXasnee
How React Uses Keys to Identify List Items EfficientlyApr 28, 2025 am 12:20 AMReactuseskeystoefficientlyidentifylistitemsbyprovidingastableidentitytoeachelement.1)KeysallowReacttotrackchangesinlistswithoutre-renderingtheentirelist.2)Chooseuniqueandstablekeys,avoidingarrayindices.3)Correctkeyusagesignificantlyimprovesperformanc
Debugging Key-Related Issues in React: Identifying and Resolving ProblemsApr 28, 2025 am 12:17 AMKeysinReactarecrucialforoptimizingtherenderingprocessandmanagingdynamiclistseffectively.Tospotandfixkey-relatedissues:1)Adduniquekeystolistitemstoavoidwarningsandperformanceissues,2)Useuniqueidentifiersfromdatainsteadofindicesforstablekeys,3)Ensureke
React's One-Way Data Binding: Ensuring Predictable Data FlowApr 28, 2025 am 12:05 AMReact's one-way data binding ensures that data flows from the parent component to the child component. 1) The data flows to a single, and the changes in the state of the parent component can be passed to the child component, but the child component cannot directly affect the state of the parent component. 2) This method improves the predictability of data flows and simplifies debugging and testing. 3) By using controlled components and context, user interaction and inter-component communication can be handled while maintaining a one-way data stream.
Best Practices for Choosing and Managing Keys in React ComponentsApr 28, 2025 am 12:01 AMKeysinReactarecrucialforefficientDOMupdatesandreconciliation.1)Choosestable,unique,andmeaningfulkeys,likeitemIDs.2)Fornestedlists,useuniquekeysateachlevel.3)Avoidusingarrayindicesorgeneratingkeysdynamicallytopreventperformanceissues.
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.
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
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
EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
Notepad++7.3.1
Easy-to-use and free code editor
