Use JavaScript functions to manipulate DOM elements and modify styles JavaScript is a powerful programming language that can be used to manipulate DOM (Document Object Model) elements and modify styles in HTML pages. In this article, we'll learn how to use JavaScript functions to perform these tasks and provide some concrete code examples. Obtaining DOM Elements To operate a DOM element, you first need to find it. We can pass the element using getElementById function

PHP website performance optimization: How to reduce DOM operations to improve access speed? In modern websites, dynamically generated content is usually implemented through DOM manipulation. However, frequent DOM operations may cause pages to load slowly and increase the load on the server. In order to optimize the performance of the website, we should reduce the number of DOM operations to increase access speed. This article will introduce some techniques to reduce DOM operations and provide corresponding code examples. Using cache variables When you need to use the generated DOM object multiple times, you can use cache variables

Vue is a very popular JavaScript framework that can be used to build high-performance, scalable single-page applications (SPA). One of the powerful features is custom directives, which are an extension of Vue's core directives (v-model, v-if, v-for, etc.) and can be used to add behaviors to DOM elements. In this article, we will learn how to use custom directives in Vue to implement DOM operations. To create a custom directive you can use Vue’s directive function to

The main reasons for slow operation of DOM are the high cost of rearrangement and redrawing and low access efficiency. Optimization methods include: 1. Reduce the number of accesses and cache read values; 2. Batch read and write operations; 3. Merge and modify, use document fragments or hidden elements; 4. Avoid layout jitter and centrally handle read and write; 5. Use framework or requestAnimationFrame asynchronous update.

The classListAPI is most recommended to operate element class names in JavaScript. 1. Use add, remove, toggle and contain methods to add, remove, switch and check classes clearly and efficiently; 2. For old browsers, you can fall back to the className attribute to manually splice strings, but it is prone to errors; 3. Determine whether the class exists and then operates it can improve logical security, but in most cases toggle is concise enough. Mastering the application scenarios and compatibility processing of classList is the key.

When operating the DOM, you should reduce the number of accesses, use modern APIs, avoid memory leaks, and combine asynchronous throttling and anti-shake. 1. Avoid frequent operation of DOM in loops. It is recommended to build strings first or use DocumentFragment to batch processing; 2. Use querySelector and querySelectorAll to improve code readability and flexibility; 3. Clean the event listener before removing elements to prevent memory leakage; 4. Use requestAnimationFrame or debounce/throttle for high-frequency events to control the execution frequency.

querySelector returns a static single element or NodeList, getElementsByClassName returns a dynamic HTMLCollection; 2. querySelector supports complex CSS selectors, the latter only supports class names; 3. QuerySelectorAll should be used when obtaining multiple elements; 4. The performance difference is extremely small, modern development recommends the use of querySelector and querySelectorAll first, because it is more flexible and has stronger code readability, and getElementsByClassName is used unless real-time collection is required.

To improve dynamic web page performance, DOM operations must be optimized to reduce re-arrangement and redrawing. 1. Avoid direct operation of DOM in loops, and batch insertion should be used for DocumentFragment; 2. Cache DOM query results, give priority to using efficient selectors such as getElementById, and limit the query scope; 3. Use event delegation to bind event listening to parent elements to reduce memory consumption; 4. Separate read and write operations to avoid layout jitter caused by forced synchronous layout; 5. Animation prioritizes CSStransform and opacity, using GPU acceleration without triggering reordering; 6. Block processing when a large number of DOM updates, through setTimeout or requestIdle