What is the principle of lazy loading

The principles of lazy loading mainly include on-demand loading, asynchronous loading, dynamic loading and delayed rendering. Detailed introduction: 1. On-demand loading is one of the core principles of lazy loading, which refers to loading corresponding resources according to user needs; 2. Asynchronous loading is another core principle of lazy loading, which refers to loading resources Loading is postponed until the user needs to use it. Asynchronous loading can be achieved by using AJAX, Fetch and other technologies, allowing data and other resources to be loaded without blocking the user interface; 3. Dynamic loading is another implementation principle of lazy loading. etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Lazy loading is an optimization technology that allows part or all of a page's resources to be loaded only when needed to reduce initial load time and network traffic. The principles of lazy loading mainly include on-demand loading, asynchronous loading, dynamic loading and delayed rendering. These principles will be introduced in detail below.

1. On-demand loading

On-demand loading is one of the core principles of lazy loading. It refers to loading corresponding resources according to user needs. In a single page application (SPA), when the user scrolls the page or performs certain interactive operations, lazy loading technology only loads the resources related to these operations instead of loading all resources at once. In a multi-page application (MPA), when a user jumps from one page to another, lazy loading technology only loads the resources required for the current page instead of loading all the resources of the entire site.

The advantage of on-demand loading is that it can reduce the initial page loading time and improve page response speed and user experience. Since only the resources users need are loaded, unnecessary network traffic and bandwidth costs can be reduced. At the same time, on-demand loading can also improve server utilization, because the server only needs to process the resources that the user needs.

2. Asynchronous loading

Asynchronous loading is another core principle of lazy loading. It refers to deferring the loading of resources until the user needs to use them. Asynchronous loading can be achieved by using technologies such as AJAX and Fetch, which allows data and other resources to be loaded without blocking the user interface.

The advantage of asynchronous loading is that it can avoid long blanks or delays when users are waiting for resources to load, improving user experience. At the same time, asynchronous loading can also reduce the burden on the server, because data or resources only need to be loaded when needed. However, asynchronous loading also requires attention to some issues, such as how to handle loading failures and how to ensure data integrity and consistency.

3. Dynamic loading

Dynamic loading is another implementation principle of lazy loading. It refers to dynamically generating and loading page content based on user behavior and needs. In lazy loading mode, page content is usually broken down into multiple small pieces, and each small piece is loaded and presented to the user only when needed.

The advantage of dynamic loading is that page content can be dynamically generated and loaded according to user needs, improving the flexibility and response speed of the page. At the same time, dynamic loading can also reduce initial page load time because only necessary structures and resources need to be loaded. However, dynamic loading also requires attention to some issues, such as how to ensure the performance and response speed of the page, how to handle page navigation and links, etc.

4. Delayed rendering

Lazy loading is often used in combination with delayed rendering technology. Delayed rendering refers to delaying the rendering process of the page until the user needs to view it. In lazy loading mode, the initial rendering of the page only contains necessary structures and resources, while other non-essential resources are loaded and presented to the user through delayed rendering.

The advantage of delayed rendering is that it can reduce the initial page loading time and improve the page's response speed and user experience. At the same time, deferred rendering can also optimize the resource management of the page, because resources only need to be loaded and rendered when needed. However, delayed rendering also requires attention to some issues, such as how to handle rendering failures and how to ensure the integrity and consistency of the page.

In short, the principle of lazy loading is mainly to postpone the loading of non-essential resources or load them on demand through technical means such as on-demand loading, asynchronous loading, dynamic loading and delayed rendering, so as to reduce the initial page loading time. Improve page response speed and user experience. At the same time, lazy loading can also save network traffic, optimize page resource management, and improve overall performance and response speed. In actual applications, you need to choose whether to use lazy loading technology based on specific needs and situations and pay attention to some potential problems to ensure the normal operation of the application and the privacy and security of users.

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