The difference between link and import is explained in detail: What are the differences between them?

In-depth analysis: What is the difference between link and import?

When developing web pages or applications, we often need to introduce external CSS files or JavaScript libraries to enhance or customize our code. In this process, link and import are two commonly used methods. Although their purpose is to introduce external resources, there are some differences in specific usage.

1. Syntax and location:

   • link: Use the link tag to link external resources to the HTML file, usually located at the head of the HTML document ( head) part. Its syntax is as follows:

     <link rel="stylesheet" type="text/css" href="styles.css">

   • import: Use the import statement to introduce external resources into the CSS file, usually at the top of the CSS file. Its syntax is as follows:

     @import url("styles.css");

2. Loading method:

   • link: During the loading process of the HTML file, the link tag will External resources and HTML files are loaded at the same time, so the loading of external resources is done in parallel. This means that the browser will download the CSS file at the same time when loading the web page and will not block the loading of the HTML file.
   • import: During the loading process of CSS files, the import statement will load external resources one by one. This means that when the browser downloads the import statement, it will stop loading the CSS file and download the introduced external resources, which will cause the loading time of the CSS file to be extended.

3. Scope of application:

   • link: can be used to introduce any type of file, such as CSS files, JavaScript files, image files, etc. It is part of the HTML language and applies to HTML files.
   • import: Mainly used to introduce CSS files. It is part of the CSS language and is suitable for CSS files. Non-CSS files cannot be introduced using the import statement.

4. Compatibility:

   • link: The link tag has good browser compatibility and supports all major browsers.
   • import: Although most modern browsers support the import statement, some older browsers may not support this syntax.

5. Introduction sequence:

   • link: Multiple link tags are loaded in sequence in the order they appear in the document.
   • import: Multiple import statements will be loaded in order of appearance in the CSS file.

To sum up, although both link and import can be used to introduce external resources, there are differences in syntax, loading method, scope of application, compatibility and introduction order. Some minor differences. Depending on the specific needs and environment, choosing the appropriate introduction method can improve the efficiency and performance of front-end development.

The following is a specific code example using link and import:

HTML file (index.html):

  <link rel="stylesheet" type="text/css" href="styles.css">


  
Hello World

CSS file (styles.css):

@import url("https://fonts.googleapis.com/css2?family=Roboto:wght@300&display=swap");

body {
  font-family: 'Roboto', sans-serif;
}

In the above example, link is used to introduce an external CSS file, and the import statement is used to introduce the Google Fonts style sheet in the CSS file. In this way, our web pages can use the Roboto font.

I hope this article can provide a deeper understanding of the difference between link and import, and help readers make more informed choices in actual development.

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