How to prevent caching in jquery

With the development of web development, the front-end framework jquery has been widely used in many websites. However, when using jquery to request data, we often encounter caching problems. If not handled in time, caching problems will cause the page to display errors or not update. This article will introduce how jquery prevents caching and its principles.

1. What is caching

Before introducing how to prevent caching, let’s first understand what caching is. When accessing a website, the browser will store the accessed data (pictures, scripts, styles, etc.) locally so that it can be read directly from the local during the next visit without having to request the server again, thus improving access speed. This process is called caching.

2. How jquery prevents caching

In jquery, the main way we prevent caching is by setting request headers. When making an AJAX request, by setting parameters such as "Cache-Control" and "Expires" in the request header, you tell the browser not to cache the request results, but to obtain the latest data from the server for each request. Here is some sample code:

1. Prevent caching in GET requests:

$.ajax({
    type: "GET",
    cache: false, //设置为false，即禁止缓存
    url: "http://www.example.com/get_data.php",
    success: function(data){
        //处理返回结果
    }
});

2. Prevent caching in POST requests:

$.ajax({
    type: "POST",
    cache: false, //设置为false，即禁止缓存
    url: "http://www.example.com/post_data.php",
    data: {
        "name": "张三",
        "age": 18
    },
    success: function(data){
        //处理返回结果
    }
});

3. Set request headers Method to prevent caching:

$.ajax({
    type: "GET",
    url: "http://www.example.com/get_data.php",
    beforeSend: function(xhr){
        xhr.setRequestHeader("Cache-Control", "no-cache");
        xhr.setRequestHeader("Expires", "0");
    },
    success: function(data){
        //处理返回结果
    }
});

3. The principle of blocking caching

After understanding how to prevent caching, let’s take a look at its principle. When setting the "Cache-Control" and "Expires" in the request header, we tell the browser not to cache the request results. The functions of these two request headers are:

1. "Cache-Control"

This request header is used to specify the caching mechanism of the request and response. It has the following values:

(1) no-cache: Forces each request to obtain the latest data from the server without using cache.

(2) max-age: Set the maximum time for resources to be cached on the client, in seconds.

(3) no-store: Disable the use of local cache.

2. "Expires"

This request header specifies the expiration time of the resource, that is, the data in the cache will be used before this time. If the browser still accesses the resource after this time, a request is sent to the server.

By setting these two request headers, we can tell the browser not to cache the request results, and obtain the latest data from the server for each request.

4. Summary

When making ajax requests, caching problems often cause us trouble. By setting the "Cache-Control" and "Expires" in the request header, we can easily prevent caching so that the page can correctly display the latest data. Hope this article is helpful to everyone.

The above is the detailed content of How to prevent caching in jquery. For more information, please follow other related articles on the PHP Chinese website!