Question

I have a piece of js code which I would really like to improve but not sure how.
The working version below has a global variable and a separate function declaration which I think could be merged into a anonymous function (Code snipped below: Not working)

Any help or pointers would be appreciated.

Working version:

var Data = {}; // would like to remove the global variable

function callBack() {
    $.ajax({
        url: "http://host/callBacks/script.js",
        //get and execute Script to process json data below
        dataType: "script"
    });
}


$(document).ready(function() {
    $.ajax({
        type: "Get",
        url: "http://host/data/json/",
        success: function(json) {
            Data = json; // Would like to just call the callback here
            callBack(Data);
        },
        error: function() {
            alert("error");
        }
    });
});


// Script which gets loaded from callBack
(function(Data) {
    var json = $.parseJSON(Data);
    $.each(json, function(i, v) {
        alert(v);
    });
})(Data);

Desired code: Not working

// Error: Length is null or not an object. In jQuery script

var Data = {}; // Ideally would like to remove this from global scope if possible

$(document).ready(function() {
    $.ajax({
        type: "Get",
        url: "http://host//data/json/",
        success: function(Data) {
            $.ajax({
                url: "http://host/callBacks/script.js",
                dataType: "script"
            });
        },
        error: function() {
            alert("error");
        }
    });
// Error: Length is null or not an object. In jQuery script

UPDATE: As per adeneo answer:
Still need to the global Data = {}; because the returned immediately executing script takes in as parameter I suppose

var Data = {};

$(document).ready(function() {
    function doAjax() {
        return $.ajax({
            type: "GET",
            url: "http://host/data/json/"
        });
    }

    var XHR = doAjax();
    XHR.done(function(data) {
        Data = data; // <--- If I remove this I get Error:'length' is not or not an object
        $.ajax({
            url: "http://host/callBacks/script.js",
            dataType: "script"
        });
    }).fail(function() {
        alert("error");
    });
});

Seems good enough though. Should probably mention that I’am testing this in IE 8. Constraint. Updated tags

Answer 1

$(function() {
    function doAjax() { //put inside function
        return $.ajax({ //return deffered object
            type: "GET",
            url: "/data/json/" //X domain not supported
        });
    }

    var XHR = doAjax();  //do ajax call
    XHR.done(function(data) { // use deffered object
        var json = $.parseJSON(data); //why would you need to get an external script just to parse some JSON?
        $.each(json, function(i, v) {
            alert(v);
        });
    }).fail(function() {
        alert("error");
    });
});