ajax.js

/*      @source: http://api.smartpay.co.ke/ajax.js
        @licstart  The following is the entire license notice for the 
        JavaScript code in this page.

        Copyright (C) 2016  Geoffrey Mureithi

        The JavaScript code in this page is free software: you can
        redistribute it and/or modify it under the terms of the GNU
        General Public License (GNU GPL) as published by the Free Software
        Foundation, either version 3 of the License, or (at your option)
        any later version.  The code is distributed WITHOUT ANY WARRANTY;
        without even the implied warranty of MERCHANTABILITY or FITNESS
        FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

        As additional permission under GNU GPL version 3 section 7, you
        may distribute non-source (e.g., minimized or compacted) forms of
        that code without the copy of the GNU GPL normally required by
        section 4, provided you include this license notice and a URL
        through which recipients can access the Corresponding Source.   


        @licend  The above is the entire license notice
        for the JavaScript code in this page.
        */
/* global ajax */

var ajax = {};
ajax.x = function () {
    if (typeof XMLHttpRequest !== 'undefined') {
        return new XMLHttpRequest();
    }
    var versions = [
        "MSXML2.XmlHttp.6.0",
        "MSXML2.XmlHttp.5.0",
        "MSXML2.XmlHttp.4.0",
        "MSXML2.XmlHttp.3.0",
        "MSXML2.XmlHttp.2.0",
        "Microsoft.XmlHttp"
    ];

    var xhr;
    for (var i = 0; i < versions.length; i++) {
        try {
            xhr = new ActiveXObject(versions[i]);
            break;
        } catch (e) {
        }
    }
    return xhr;
};

ajax.send = function (url, callback, method, data, async) {
    if (async === undefined) {
        async = true;
    }
    var x = ajax.x();
    x.open(method, url, async);
    x.onreadystatechange = function () {
        if (x.readyState == 4) {
            callback(x.responseText)
        }
    };
    if (method == 'POST') {
        x.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
    }
    x.send(data)
};

ajax.get = function (url, data, callback, async) {
    var query = [];
    for (var key in data) {
        query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
    }
    ajax.send(url + (query.length ? '?' + query.join('&') : ''), callback, 'GET', null, async)
};

ajax.post = function (url, data, callback, async) {
    var query = [];
    for (var key in data) {
        query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
    }
    ajax.send(url, callback, 'POST', query.join('&'), async)
};