Set css cache

With the continuous development of Web technology, CSS (Cascading Style Sheets) has also played an increasingly important role in web design. However, for large websites, the loading speed of CSS files can become an issue. To solve this problem, caching is a very useful method. This article will explain how to set up CSS caching on your web server to improve the performance of your website.

What is CSS caching?

When visiting a website, the browser will request HTML, CSS, JavaScript and other resources from the web server. Because these resources can vary in size, so can their load times. In order to speed up website loading, the browser caches a resource locally the first time it is requested. When the same resource is requested next time, the browser will obtain the resource from the local cache, avoiding requesting the resource from the web server again, thus improving the performance of the website.

CSS caching is a special caching mechanism that allows browsers to cache CSS files so the page loads faster on subsequent visits. If the CSS cache is set up correctly, the browser no longer needs to re-download the CSS file when visiting the same website, thereby improving the loading speed of the web page.

How to set up CSS cache?

The following are some methods that can help you set up CSS caching on the web server to improve the performance of the website:

1. Set HTTP response headers

To set CSS To cache, you need to set HTTP response headers on the server. The HTTP response header is information sent by the server to the browser. It contains metadata about the resource, such as whether it can be cached, the cache time, etc. To set up CSS caching, you need to set two HTTP response headers: "Cache-Control" and "Expires".

1.1 Cache-Control

You can control how the browser caches CSS files by setting the "Cache-Control" response header, such as Cache-Control:public. Public here means that this CSS file can be cached by all users and all proxy servers, such as CDN (Content Delivery Network) servers. Another commonly used setting is: Cache-Control:max-age=31536000, where 31536000 refers to the number of seconds, which is one year. In this way, the browser will cache the CSS file for one year.

1.2 Expires

Another way to set up CSS caching is by using "Expires" in the HTTP response header. This response header specifies the expiration time of the resource. When the browser requests a resource for the first time, the server will attach an expiration time to the HTTP response header. Before the expiration time is reached, the browser will no longer request the resource from the server. For example, if you set the expiration time to one year, then every time you visit within a year, the browser will get the CSS file from the local cache without making another request to the server.

2. Use the file name version number

Sometimes, when you update a CSS file, you want the browser to re-download the file instead of getting it from the cache. This can be achieved by adding the version number to the file name. When you update a CSS file, increase the version number in the file name by one value. For example, rename style.css to style_v2.css. This way the browser won't get the old CSS file from the cache because it will think it's a new file.

3. Use CDN

CDN is a content distribution network that can store your CSS files on multiple server nodes around the world to shorten user request time for CSS files. If you use a CDN to distribute your CSS files, you can fetch the files from the CDN's cache, which will significantly increase the page loading speed.

Summary

Setting up CSS caching on your web server is a simple and effective way to improve website performance and reduce page load times. By setting HTTP response headers, using filename version numbers, and using CDNs, you can maximize browser caching to reduce requests to the web server, making your website faster and more efficient.

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