jquery ajax synchronous request lock

When developers use jQuery's Ajax to make network requests, sometimes we need to make synchronous requests. For example, in some cases, we need to wait for the result of the request before performing other operations. However, in Ajax, synchronous requests have a flaw, that is, synchronous requests will lock the browser, preventing the user from performing other operations until the request is completed or times out.

So how to solve this problem? We can solve this problem by writing a function that can turn on and off synchronous requests, so that when synchronous requests are needed, they can be turned on, and when they are not needed, they can be turned off.

Next, let’s take a look at how to implement this function.

First, we need to define a variable to save the current status of whether a synchronous request is required:

var isSync = false;

Next, we define a function to set the synchronous request status:

function setSync(status) {
    isSync = status;
}

Among them, the status parameter is a Boolean value, indicating the synchronization request status that needs to be set.

Next, we need to monitor each Ajax request and make a judgment before the request. If the current status is a synchronous request, then we will set it as a synchronous request; otherwise, we will set it as an asynchronous request. .

$(document).ajaxSend(function(event, xhr, options) {
    if (isSync) {
        options.async = false; // 设置同步请求
    } else {
        options.async = true; // 设置异步请求
    }
});

Finally, we need to set the status to an asynchronous request after each Ajax request is completed to prevent the next request from being processed as a synchronous request.

$(document).ajaxComplete(function(event, xhr, options) {
    options.async = true; // 设置为异步请求
});

Now that we have defined a function that can turn on and off synchronous requests, then when we need to use synchronous requests, we can call setSync(true) to turn on synchronous requests and call setSync(false) to turn off ask.

For example, the following code implements a synchronous request:

setSync(true); // 开启同步请求
$.ajax({
    url: '/api/data',
    type: 'GET',
    dataType: 'json',
    success: function(data) {
        console.log(data); // 处理返回结果
    },
    error: function(xhr, errorType, error) {
        console.error(error); // 处理请求错误
    }
});
setSync(false); // 关闭同步请求

In actual development, we should try to avoid using synchronous requests, because synchronous requests will affect the user experience. However, in some cases, such as logging in and other operations that must wait for the result, we can use the above method to solve the problem of synchronous request locking the browser.

In short, when using Ajax to make network requests, we should handle synchronous requests very carefully to avoid affecting the user experience.

The above is the detailed content of jquery ajax synchronous request lock. For more information, please follow other related articles on the PHP Chinese website!