ajax{} | JavaScript object | AJAX methods object

ajax.demo.js

// examples
;(function () {

  ajax.json('file.php', {best: "cats", awesome: "javascript"}, function (json) {
    
     var foo = document.getElementById('foo');
     for (var ii = 0, len = json.length; ii < len; ii++) {
        foo.innerHTML += '<li>' + json[ii].name + ': ' + json[ii].details + '</li>';
     }
  });

  ajax.load('example.html', '', function (xhr) {
    
    document.getElementById('bar').innerHTML = xhr.responseText;
    
  });

})();

ajax.js

/**
 * AJAX
 * ------------------------------------------------------------------------
 * ajax{}
 * @version 1.0 | April 23rd 2013
 * @author  Beau Charman | @beaucharman | http://beaucharman.me
 * @link    https://gist.github.com/beaucharman/5384446/
 * @method  load
 * @method  json
 * @method  toQueryString
 *
 * Some AJAX and JSON helper functions.
 * Todo
 *   1. callback that simply returns the value
 *   2. send params as object
 * ------------------------------------------------------------------------ */
var ajax = {

  /**
   *  Load
   * ------------------------------------------------------------------------
   * ajax.load()
   * @param {string}   url
   * @param {object}   data
   * @param {function} callback
   *
   * AJAX loads data from url.
   * ------------------------------------------------------------------------ */
  load: function (url, data, callback) {
    
    var xhr;
    data = (data) ? this.toQueryString(data) : '';

    /* Get the xmlhttp request method */
    if (window.XMLHttpRequest && typeof XMLHttpRequest !== 'undefined') {
      
      xhr = new XMLHttpRequest();
      
    } else if (window.ActiveXObject) {
      
      var versions = [
        "MSXML2.XmlHttp.5.0",
        "MSXML2.XmlHttp.4.0",
        "MSXML2.XmlHttp.3.0",
        "MSXML2.XmlHttp",
        "Microsoft.XmlHttp"
      ];
      
      for (var ii = 0, ln = versions.length; ii < ln; ii++) {
        
        try {
          xhr = new ActiveXObject(versions[ii]);
          break;
        }
        catch(e){}
      }
    }

    /* Capture and act on state changes */
    xhr.onreadystatechange = function() {
      
      if (xhr.readyState !== 4 || xhr.status !== 200) {
        
        return;
      }
      
      callback(xhr);
    };

    xhr.open('POST', url, true);
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr.send(data);
  },

  /**
   * JSON
   * ------------------------------------------------------------------------
   * ajax.json()
   * @param {string}   url
   * @param {object}   data
   * @param {function} callback
   *
   * Loads and then parses JSON data from url.
   * ------------------------------------------------------------------------ */
  json: function (url, data, callback) {
    
    this.load(url, data, function (xhr) {
      
      callback(JSON.parse(xhr.responseText));
    });
  },

  /**
   * To Query String
   * ------------------------------------------------------------------------
   * ajax.toQueryString()
   * @param  {object} obj
   * @return {string}
   *
   * Converts a javaScript object into a URL friendly query string.
   * ------------------------------------------------------------------------ */
  toQueryString: function (obj) {
    
    var str = '';
    var ln;
    
    for (var pro in obj) {
      str += pro + '=' + obj[pro] + '&';
    }
    
    ln = str.length;
    return str.slice(0, ln - 1);
  }
};