A small AJAX library

gistfile1.js

function $xhr(url, success, fail) {
    var _url = url;
    var me = this;
    var seperator = 'sdfsdfsdfdsweriweournClkjwa'; //TODO: Replace with a real pseudo random string generator

    me.data = {};

    function request_success(x) {
        return (x.status == 200) || (x.status == 304);
    }

    function createXHR(method, url) {
        var _xhr = XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");

        _xhr.onreadystatechange = function () {
            if (_xhr.readyState == 4) {

                console.log(_xhr.status);

                var is_success = me.SucessCondition && typeof (me.SuccessCondition) == 'function'
  				? SuccessCondition(_xhr) : request_success(_xhr);

                if (is_success)
                {
                    if (success != null)
                    {
                        var responseData;
                        var content_type = _xhr.getResponseHeader('Content-Type');

                        if (content_type == null)
                            content_type = '';

                        if (content_type.search(/json/i) >= 0)
                            eval('responseData=' + _xhr.responseText);

                        if (content_type.search(/xml/i) >= 0)
                            responseData = _xhr.responseXML;

                        if (content_type.search(/script/i) >= 0)
                            eval(_xhr.responseText);

                        if (responseData == null)
                            responseData = _xhr.responseText;

                        success(responseData);
                    }
                }
                else
                {
                    if (fail != null)
                        console.log(_xhr);
                }
            }
        }

        url = url ? url : _url;

        if (url == null)
            throw 'URL IS NULL';

        _xhr.open(method, url);

        return _xhr;
    }

    function createDataString(obj) {
        if (obj == null)
            return null;

        var xs = new Array();

        for (p in obj) {
            if (obj.hasOwnProperty(p) && (typeof (obj[p]) != 'function')) {
                var __name = encodeURIComponent(p);
                var split = (obj[p].toString()).split(seperator);

                var array = new Array();

                for (var i = 0; i < split.length; i++)
                    array.push(encodeURIComponent(split[i]))

                var __val = array.join(',');

                xs.push(__name + '=' + __val);
            }
        }

        return xs.length > 0 ? xs.join('&') : null;
    }

    this.get = function (url) {
        createXHR('get', url).send();
    }

    this.post = function (url) {
        var xhr = createXHR('post', url);
        var payload = createDataString(me.data);

        if (payload != null && payload.length > 0) {
            xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            xhr.setRequestHeader('Accept', 'application/json');
            console.log(payload);
            xhr.send(payload);
        }
        else {
            xhr.send();
        }
    }

    function ensureDataObject() {
        if (me.data == null)
            me.data = {};
    }

    this.setData = function (obj) {
        if (arguments.length > 1) {
            ensureDataObject();
            me.data[arguments[0]] = arguments[1];

            return true;
        }


        var __id = null;

        var successful_data_extraction = false;

        if (!obj)
            return false;

        if (typeof (obj.checked) == 'boolean' && obj.type == 'checkbox' && !obj.checked)
            return false;

        if (typeof (obj) == 'string')
            return this.setData(document.getElementById(obj));

        if (obj.toString == '[object HTMLFormElement]')
            return this.setData(obj.childNodes);

        ensureDataObject();

        

        if (obj.length && parseInt(obj.length, 10) > 0) {
            var len = obj.length;

            for (var i = 0; i < len; i++) {
                var elem = obj[i];

                if (typeof (elem.checked) == 'boolean' && elem.type == 'checkbox' && !elem.checked)
                    continue;

                if (elem.name)
                    __id = encodeURI(elem.name)
                else
                    if (elem.id)
                        __id = encodeURI(elem.id);

                if (__id != null) {
                    if (elem.selectedOptions) {
                        var selected = new Array();
                        var items = elem.selectedOptions;
                        var len = items.length;

                        for (var i = 0; i < len; i++)
                            selected.push({ name: elem.name, value: elem.value });

                        return this.setData(selected);

                    }
                    else
                        if (elem.value) {
                            if (me.data[__id])
                                me.data[__id] += seperator + elem.value;
                            else
                                me.data[__id] = elem.value;

                            successful_data_extraction = true
                        }
                }
            }
        }
        else {            

            __id = obj.name || obj.id;

            if (__id != null && obj.value) {
                me.data[__id] = obj.value;
                successful_data_extraction = true
            }
            else {
                me.data = obj;
                successful_data_extraction = true
            }
        }

        return successful_data_extraction;
    }
}