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In today's Internet age, the loading speed of a website is crucial to user experience and SEO rankings. Optimizing the front-end performance can significantly improve the loading speed of the website and provide users with a better access experience. This article will introduce some common front-end performance optimization techniques, and use an example to illustrate how to apply these techniques to improve website loading speed.
1. Compress and merge files
Minifying and combining CSS and JavaScript files can reduce the size and number of files, making your website load faster. By using tools such as UglifyJS and CSSNano, files can be automatically compressed and merged.
Sample code:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="styles.css">
<script src="script1.js"></script>
<script src="script2.js"></script>
</head>
<body>
<!-- 网页内容 -->
</body>
</html>
Optimized code:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="styles.min.css">
<script src="scripts.min.js"></script>
</head>
<body>
<!-- 网页内容 -->
</body>
</html>
2. Using cache
Using browser cache can reduce the number of requests to the server, thereby improving the loading speed of the website. By setting the Cache-Control and Expires fields in the HTTP response header, you can specify the file cache time.
Sample code:
app.use(express.static('public', {
maxAge: '1d'
}));
3. Image optimization
Images are often the most bandwidth-intensive resource on a website. By using techniques such as proper image formatting, compression, and lazy loading, you can reduce the size and number of images, thereby improving the loading speed of your website.
Sample code:
<img src="image.jpg" alt="Image" loading="lazy">
4. Use CDN to accelerate
Using a content distribution network (CDN) can distribute the static resources of the website to servers around the world, thereby speeding up the loading of resources. CDN acceleration can be achieved by replacing the URL of the static resource with the URL of the CDN.
Sample code:
<link rel="stylesheet" href="https://cdn.example.com/styles.min.css">
<script src="https://cdn.example.com/scripts.min.js"></script>
5. Asynchronous loading
Loading JavaScript code asynchronously avoids blocking page rendering and loading. Asynchronous loading can be achieved by marking the script as async or defer.
Sample code:
<script src="script.js" async></script>
Through the above optimization techniques, we can significantly improve the loading speed of the website and provide a better user experience. In actual development, we can use these technologies in combination, and adjust and optimize according to specific situations to achieve the best performance.