Summary of JavaScript-based Web application performance monitoring and optimization experience

With the increasing popularity of Web applications, the performance of Web applications has become one of the challenges that Web developers often face. In the initial development stage of web applications, we need to optimize application performance through various means to ensure that users get the best user experience. After the Web application is launched, we need to configure a monitoring system to monitor the performance of the Web application in real time to improve the stability and user satisfaction of the Web application. In this article, we will share some experience summaries of JavaScript-based web application performance monitoring and optimization.

1. The main challenge of Web application performance optimization

The main challenge of Web application performance optimization is to improve page access speed and page rendering speed. Specifically, this requires us to consider the following aspects:

1. Reduce the number of HTTP requests

HTTP requests are one of the bottlenecks of Web application performance. Therefore, we need to reduce the number of HTTP requests to improve page access speed. Specific methods can be to merge CSS and JavaScript files, compress images, etc.

2. Optimize the code structure and format

Optimizing the code structure, format and keyword naming convention is also one of the effective ways to improve the code running speed. For example, reduce the number of nesting levels, reduce redundant code, etc.

3. Use CDN

Using CDN (content distribution network) can significantly improve the access speed of web applications. Servers that allow users to quickly access web applications, especially international users.

4. Reduce DOM operations

Frequent DOM operations will have a significant impact on the performance of web applications. Therefore, we need to reduce DOM operations, optimize JavaScript operation methods, and reduce searches, calls, and redraws in the DOM through JS variable caching.

2. Main indicators of Web application performance monitoring

In the process of Web application development and testing, we need to monitor some key indicators to evaluate the performance of Web applications. These indicators include:

1. Page loading time

For users, page loading time is one of the important criteria for measuring the performance of web applications. We can obtain network request, page resource loading time, DOM loading time and other data through the browser's developer tools.

2.HTTP response time

HTTP response time can reflect the stability and performance of the web application server. If the HTTP response takes too long, it may mean that the server is overloaded or there is a problem with the network connection. HTTP response times can be displayed via network request data.

3. User interaction performance

User interaction performance is another key indicator that identifies the performance of web applications, including the response time of the page and the clarity of visual effects. You can use JS to collect user operation interaction events, analyze the data information of its operation and response time, and find the critical value of response time under different user operation requirements.

3. Tools and technologies for Web application performance monitoring

In order to implement performance monitoring of Web applications, we need to use some specialized tools and technologies. The following introduces several commonly used tools and technologies:

1. Google PageSpeed ​​Insights

Google PageSpeed ​​Insights is a free performance evaluation tool officially launched by Google that can quickly check the Web Application performance bottlenecks and provide performance optimization suggestions. It provides some commonly used web application performance indicators and basic SEO suggestions, and can conduct extensive inspection and evaluation of the universal performance of web applications.

2. Webpagetest

Webpagetest is a free online performance testing tool that can provide information about page loading speed, total downloads, response time and performance variance of each component. Information. In this way, web developers can clearly understand which optimization points need to be optimized.

3. Requestly

Requestly is a free Chrome browser plug-in that can be used to modify the browser's requests and responses. Through it, we can simulate some different network connections and client configurations to test the performance of web applications and locate performance bottlenecks.

4. Simulator and real machine testing

Simulator and real machine testing can help us test the performance of web applications on different browsers and devices. Through testing on different devices or browsers, the data analysis methods and results of the performance of web applications under different network environments and processor internal conditions can be accelerated.

4. Best Practices for Optimizing Web Application Performance

In the actual development process, we need to adopt appropriate optimization methods based on the actual situation of the Web application to optimize the performance of the Web application. For example:

1. Reduce the number of HTTP requests, merge and compress CSS, JS, and image files;

2. Use CDN to improve the access speed of web applications;

3. Optimize the loading order and writing order of CSS and JS files and standardize code management;

4. Optimize database design, reduce the number of queries, and improve execution speed.

5. Use asynchronous loading and processing methods as much as possible;

6. Reduce DOM operations and optimize JavaScript operation methods to reduce code query operations;

7. Use browser cache;

8. Comprehensive automation of the project;

In short, the performance optimization of Web applications requires us to continuously practice and summarize experience, and accumulate methods and techniques for continuous optimization. These methods and techniques can significantly improve the performance of web applications, giving them a better user experience and higher user satisfaction.

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