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This article mainly explains the "Web front-end performance optimization methods have", the content of the article is simple and clear, easy to learn and understand, the following please follow the editor's ideas slowly in-depth, together to study and learn "what are the Web front-end performance optimization methods?"

The result of Web front-end performance optimization directly affects the user experience, and the user experience is closely related to the satisfaction of the website. Therefore, the optimization of Web front-end is very important. Although Web front-end engineers also make this a top priority, what makes them tricky is that they don't know where to optimize. In fact, Web front-end optimization is not difficult, just need to master some practical skills, you can easily deal with it. Next, we will provide you with some optimization methods.

1. Reduce the number of HTTP requests

(1) avoid redirection: redirection indicates that further action by the client is required to complete the request, and the request time will be extended. Therefore, you should use the most complete and direct address when entering URL.

(2) the mechanism of using cache: database cache, server cache (reverse proxy and CDN cache), browser cache.

Pictures are loaded lazily.

In the case of a large number of pictures on the page, you can use lazy loading. Only the picture of the first screen is loaded, and the corresponding picture is loaded when the user scrolls to access the following content. The method is to first replace the picture with a tiny placeholder map, which only needs to be downloaded once, store the src of the original picture in another attribute, and judge that when the picture is about to enter the visual area, the path will be assigned to src and the picture will be downloaded for display.

Third, code optimization

(1) the structure of the page: CSS is placed at the top of the HTML content, and JavaScript is placed at the bottom of the HTML content. You can use preload to resolve the DNS of a resource in advance. Because browsers read content from top to bottom, the location where the resources are placed affects the access speed of the site. For example, if you place the script tag in front of the HTML content, the browser will first call the JavaScript interpreter to parse the JS, and then render the rest of the HTML content. For users, what they can see is the content of HTML, so doing so will cause a delay in the usability of the page.

(2) JavaScript optimization: such as reducing the operation of DOM, reducing rearrangement and redrawing, reducing scope chain search, cautious use of eval function and so on. The optimization of JS code and CSS requires front-end developers to have a clear understanding of the principles of page rendering and a solid grasp of the basics.

(3) CSS optimization: reduce the use of wildcards, extract common styles to enhance reusability, accurate selectors can reduce matching time, moderate use of inline styles.

In fact, more often than not, the difficulty of Web front-end optimization depends on your proficiency and practical experience.

Thank you for your reading, the above is "what are the optimization methods of Web front-end performance?" after the study of this article, I believe you have a deeper understanding of what the optimization methods of Web front-end performance have, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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