Tips for improving page performance with JavaScript

With the development of the Internet, website performance is becoming more and more important. Page speed has a significant impact on both user experience and search engine rankings. Therefore, improving page performance is a key aspect of website optimization. This article will introduce some techniques to improve page performance through JavaScript.

1. Reduce HTTP requests:

HTTP requests are one of the main reasons for slow website speed. When the browser requests a page, it needs to send multiple HTTP requests to obtain files such as CSS, JavaScript, and images. These requests take time, so reducing them is critical to improving page speed.

You can use the following tips to reduce HTTP requests:

1. Combine CSS and JavaScript files:

Combine multiple CSS and JavaScript files into a single file The number of HTTP requests can be reduced, thereby increasing website speed. This can be achieved by using build tools like Gulp or Webpack.

2. Use image sprites:

Merge multiple small icons into a single image file and use CSS to crop out the required parts, you can reduce the HTTP of the image file Number of requests. This is called image sprite technology.

3. Use Base64 encoding:

Embedding small images into CSS through Base64 encoding can reduce the number of HTTP requests. But for large image files, this method is not recommended.

2. Lazy loading:

Lazy loading refers to loading certain resources when they are used. Using this technique reduces initial load time, thereby improving page speed and user experience.

You can try the following lazy loading techniques:

1. Lazy loading of images:

Set the src attribute of the image to a placeholder, and then add it to the page When scrolling to the image position, set the src attribute to the actual image URL. This technique is called lazy loading or delayed loading.

2. Lay-loading JavaScript:

Lay-load unnecessary JavaScript code to the bottom of the page so that page content loads faster. It is recommended to use async or defer attributes, which allow JavaScript files to be loaded asynchronously without interrupting page rendering.

3. Optimize code:

Optimizing JavaScript code is the key to improving page performance. Here are some tips to consider:

1. Optimize loops:

Avoid doing a lot of calculations or I/O operations in loops, you can use caching or transforming data structures, etc. Method to optimize the loop.

2. Avoid double calculations:

Save the results and reuse them instead of performing the same calculation operation multiple times.

3. Eliminate memory leaks:

Ensure that objects, variables, and event handlers are removed when they are no longer used to avoid memory leaks.

4. Compression code:

Compression can reduce the size of JavaScript files, thereby reducing download time. You can use the following tips to minify JavaScript code:

1. Use a minifier:

Use a JavaScript minifier like UglifyJS to remove unnecessary code, shorten variable names and Compress code into smaller files.

2. Enable Gzip:

Enabling Gzip compression on the server can reduce file size by approximately 70%, thus speeding up downloads.

Summary:

By using JavaScript techniques to improve page performance, you can improve page speed and user experience, thereby increasing search engine rankings and user satisfaction. The above tips are only part of improving page performance, there are many other aspects to consider, such as response time, caching, etc. Therefore, comprehensive optimization is necessary for website optimization.

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