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How to link javascript in html

WBOYOriginal: 2023-05-09 15:33:073387browse

In Web development, Javascript is widely used in website form validation, animation effects, interactivity, etc. In order to enable Javascript, we need to link a JS file in the HTML. This article will explain how to link Javascript in HTML.

1. Embed Javascript

The most basic method is to embed Javascript code directly in the HTML page without linking to any files in the HTML document. As shown below:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>嵌入Javascript</title>
</head>
<body>
    <script>
      //在这里写Javascript代码
    </script>
</body>
</html>

The method of embedding Javascript code is suitable for very simple functional requirements, which is the fastest way across platforms.

2. External link Javascript files

When the amount of Javascript code gradually increases, we need to write the code in a separate .js file, and then link the .js file in HTML. Load the entire Javascript program. We can create a new .js file, copy and paste the Javascript code into the file, and then link the file in the HTML page. As shown below:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>外链Javascript</title>
</head>
<body>
    <script src="helloworld.js"></script>
</body>
</html>

The "src" attribute specifies the path to link to the external Javascript file. In the above example, the file name is "helloworld.js". Note that the file path needs to be specified relative to the location of the HTML file.

3. Link to external CDN library

Under normal circumstances, we can obtain the Javascript library from the CDN (content distribution network) to reduce the load on the server and obtain faster web page loading speed. For example, libraries like jQuery and Bootstrap are available from Google and Bootstrap CDN. Using a CDN often requires changing the link path in your code to the CDN's link. As shown below:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>链接CDN库</title>
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>
    <!-- 在这里调用jQuery代码 -->
</body>
</html>

In the above example, we used jQuery’s CDN link. Please note that when using a CDN, you should choose to report a relatively stable CDN address and use an https link to ensure website security.

This article introduces various ways to link Javascript in HTML: embedding Javascript, externally linking Javascript files, and linking to external CDN libraries. The first two methods are suitable for small projects, while external CDN libraries are suitable for large projects with high reliability and speed. In actual web development, we can choose an appropriate method for Javascript linking based on the actual situation, needs and security of the project.

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