从jQuery Ajax返回值

Question

I am trying to return a value from a completed jQuery Ajax call. However, instead of the JSON data, I am receiving back "undefined." How can I modify my code to get the JSON data instead of undefined?

function callback(data) {
    return data;
}

var xv = jQuery.ajax( {
    url: 'http://www.domain.com/json.php',
    dataType: 'json',
    success: function(data) {
        alert('Success.'); // This is alerted.
    },
    error: function(data) {
        alert('File could not be processed.'); // This is not alerted.
    },
    complete: function(data) {
        callback(data);
    }
});

console.log(callback()); // Getting "undefined" here instead of data.

Answer 1

You aren't actually storing data anywhere. All you do is reflect back whatever is given to you, just like Sterling said

I would modify it like so:

var globalData;
function(callback){
  globalData = data;
}

Then console.log(globalData) and you can see the result

Answer 2

AJAX is async by default, you have your data only when you get it, that's in your success callback. Do a sync call, or use your data inside your success function.

Your code should look like this instead:

function doWithJson(data) {
    console.log(data);
}
var xv = jQuery.ajax( {
    url: 'http://www.domain.com/json.php',
    dataType: 'json',
    success: function(data) {
        doWithJson(data);
    },
    error: function(data) {
        alert('File could not be processed.');
    },
    complete: function(data) {
        /* Remove overlay */
    }
});