JQuery ajax调用的返回值 [英] Return value of JQuery ajax call

问题描述

我希望这个函数返回 ajax 调用是否成功.有什么办法可以做到这一点吗?我下面的代码没有这样做.

I want this function to return wether or not the ajax call was succesful or not. Is there any way I can do this? My code below doesn't do this.

function myFunction(data) {
var result = false;
$.ajax({
    type: "POST",
        contentType: "application/json",
        dataType: "json",
        url: "url",
        data: data,
        error: function(data){
             result = false;
             return false;
        },
        success: function(data){
            result = true;
            return true;
        }
     });
     return result;
}

推荐答案

很遗憾，您无法将值返回给包装异步回调的函数.相反，来自 AJAX 请求的成功回调会将数据和控制权移交给另一个函数.我在下面演示了这个概念:

Unfortunately, you cannot return values to functions that wrap asynchronous callbacks. Instead, your success callback from the AJAX request will handoff the data and control to another function. I've demonstrated this concept below:

myFunction 的定义:

// I added a second parameter called "callback", which takes a function
 // as a first class object
function myFunction(data, callback) {
    var result = false;
    $.ajax({
        type: "POST",
        contentType: "application/json",
        dataType: "json",
        url: "url",
        data: data,
        error: function(data){
            result = false;

            // invoke the callback function here
            if(callback != null)  {
                callback(result);
            }

            // this would return to the error handler, which does nothing
            //return false;
        },
        success: function(data){
            result = true;

            // invoke your callback function here
            if(callback != null) {
                callback(result);                
            }

            // this would actually return to the success handler, which does
              // nothing as it doesn't assign the value to anything
            // return true;
        }
     });

     // return result; // result would be false here still
}

回调函数定义:

// this is the definition for the function that takes the data from your
 // AJAX success handler
function processData(result) {

    // do stuff with the result here

}

调用你的 myFunction:

var data = { key: "value" }; /* some object you're passing in */

// pass in both the data as well as the processData function object
 // in JavaScript, functions can be passed into parameters as arguments!
myFunction(data, processData);

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