Understand various caching mechanisms of H5

The caching mechanism provided by H5 includes: 1. Browser cache: stores the recently accessed resources and needs to control the Cache-Control header; 2. Server cache: managed by the server; 3. Offline cache: allows loading when there is no network, and a Service Worker needs to be created. Choosing the right caching strategy depends on the frequency of the resource update, helps increase loading speed, reduce server load and optimize user experience.

H5 cache mechanism

H5 provides a variety of caching mechanisms designed to improve the performance and user experience of web applications. These mechanisms reduce the number of requests to the server and speed up page loading times by storing and reusing previously downloaded data. Here is a detailed overview of the H5 caching mechanism:

Browser cache

The browser cache stores recently accessed resources such as images, CSS, and JavaScript files. When the user revisits the page, the browser loads these resources from the cache instead of requesting them again from the server. Browser cache can be controlled in the following ways:

• Cache-Control HTTP header
• Browser settings

Server side caching

The server cache is managed by the web server and stores the responses issued by the server. When the client requests a resource, the server checks whether the resource exists in its cache. If present, the server will provide the resource from the cache instead of regenerating it. Server cache can be controlled in the following ways:

• Expires HTTP header
• Last-Modified HTTP header
• ETag HTTP header

Offline cache

Offline caching allows web applications to load without an internet connection. It is done by storing critical resources on the local device and creating a Service Worker. The Service Worker acts as a proxy for the application and decides whether to request data from the server or provide data from the local cache.

Choose the right caching policy

Choosing the appropriate caching strategy depends on the specific needs of the application. For frequently changing resources (such as news articles), shorter cache expiration times can be used. For resources that change less frequently, such as CSS files, a longer cache expiration time can be used.

Advantages of caching mechanism

• Improve page loading speed
• Reduce server load
• Improve user experience
• Save bandwidth

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