Do not write after jquery

jQuery will not be written later: How to optimize your front-end code

With the development of Internet technology, front-end development is becoming increasingly complex and diversified. The continuous development and updating of front-end frameworks and libraries have made front-end programming more convenient. Among them, jQuery, as a widely used JavaScript library, is widely praised for its flexibility and ease of use. However, when using jQuery, sometimes in order to pursue effects or visual effects, we often write a lot of complex code, which has a direct impact on our page performance and user experience. In this article, we will introduce how to optimize the use of jQuery to help you improve the performance and user experience of your website.

1. Reduce DOM operations

jQuery is a library based on DOM operations, and DOM operations are usually one of the slowest operations in JavaScript execution. Therefore, when we use jQuery to access DOM nodes, we need to minimize the number of DOM operations. Selectors commonly used in jQuery can be implemented directly through the DOM API, which can avoid unnecessary traversal of DOM elements by jQuery. In addition, if you want to operate the same DOM element multiple times, you can consider saving it in a variable before operating it, which can reduce the amount of code and the number of DOM operations.

2. Appropriate use of chain calls

jQuery’s chain calls allow us to write more concise code, but excessive use of chain calls may affect the readability of the code. readability and performance. The longer the chain of calls is, the more each method call needs to wait for the return value of the previous method, which will generate many anonymous objects and affect the performance of the code. Therefore, we need to use chain calls under appropriate circumstances, for example, multiple similar operations can be processed using chain calls.

3. Cache the selector

When we need to access the same element multiple times, it is best to cache the selector into a variable, which can improve code efficiency , to avoid searching the DOM tree every time. If you reuse the selector in the page, you can consider caching the selector in a global variable to avoid executing the same selector multiple times.

4. Reduce querying of documents

When using jQuery, we need to note that several commonly used methods will query the entire document, which will affect performance. Have a big impact. For example, $("body"), $("html") and other methods will query the entire document. In practical applications, we can narrow the query scope of the document to specific elements by adding class names or IDs, thereby reducing the query of the entire document.

5. Merging styles and scripts

In the process of using jQuery on the page, using a single file to merge styles and scripts can significantly reduce the number of HTTP requests, thereby greatly improving Page performance. Placing styles and scripts in the same file can reduce network load by reducing HTTP core request times and latency.

6. Use appropriate event handlers

When using jQuery, we should try to avoid using event handlers too frequently. For example, the $(window).resize() method will frequently trigger window size events when the window is resized and require frequent redrawing of the HTML DOM. This can result in a significant performance degradation. Therefore, we can use libraries such as _.debounce or _.throttle to limit the execution frequency of event handlers.

7. Reasonable use of proxies

jQuery provides an event proxy mechanism, which allows us to bind event handlers to Document or any other DOM node, and can handle Events for descendant elements of these nodes. Event delegation is often a way to optimize DOM performance. Proper use of event delegation can reduce the number of event listeners, thereby reducing memory usage and DOM operations. For example, we can bind an event handler to a parent element so that the event is triggered on subsequently added child elements.

Summary

In practical applications, we need to optimize our code to improve website performance and user experience. Using the jQuery library helps write elegant and efficient code, but using the library and framework correctly is a must. There are some best practices we can adopt to reduce code size and code complexity, thus improving application performance. With the methods described in this article, we can easily make our site perform better, thus increasing user satisfaction and loyalty.

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