调用函数时变得不确定

Question

I have this function which parses the JSON. I am getting undefined when I am calling it in a .live function.

Here is the function that I have created,

function getAbc() {
                    var details;
                    var id = $(this).attr('data-id');
                    $.ajax({
                        url : '/index.php/data',
                        type : 'GET',
                        data : 'persons[]=' + id,
                        success : function(data, textStatus, xhr) {
                            details = JSON.parse(data);
                        },
                    });
                    return details;
                }

I am simply calling like this, getAbc(). And is there any way that I can access details variable in the function?

Answer 1

Use continuation passing style. The $.ajax is async in nature.

function getAbc(callback) {
    var details;
    var id = $(this).attr('data-id');
    $.ajax({
       url : '/index.php/data',
       type : 'GET',
       data : 'persons[]=' + id,
       success : function(data, textStatus, xhr) {
           details = JSON.parse(data);
           callback(details);
       }
    });
}

function getAbc(function (details) {
    console.log(details);
});

Answer 2

That's because ajax happens asynchronously . That means getAbc returns before success is invoked, because the request goes over the wire. You need to use details in the success callback, not after the getAbc method returns. Alternatively, in success call another method that uses details, and pass details to that method.

Answer 3

This is due to the way AJAX works.

AJAX requests are asynchronous, which means they do not return immediately.

When you make an AJAX call, a request is made that completes at an unknown time.

You can use a callback function to handle the results.

A callback function is a function that gets executed AFTER the response is received from the AJAX request.

You can specify a callback function and pass it to your AJAX call.