XML to JSON converter function

XMLtoJSON.js

// Converts XML to JSON
// from: http://coursesweb.net/javascript/convert-xml-json-javascript_s2
function XMLtoJSON() {
  var me = this;      // stores the object instance

  // gets the content of an XML file and returns it in 
  me.fromFile = function(xml, rstr) {
    // Creates an instance of a XMLHttpRequest object
    var xhttp = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");
    // sets and sends the request for calling "xml"
    xhttp.open("GET", xml ,false);
    xhttp.send(null);

    // gets the JSON string
    var json_str = jsontoStr(setJsonObj(xhttp.responseXML));

    // sets and returns the JSON object, if "rstr" undefined (not passed), else, returns JSON string
    return (typeof(rstr) == 'undefined') ? JSON.parse(json_str) : json_str;
  }

  // returns XML DOM from string with XML content
  me.fromStr = function(xml, rstr) {
    // for non IE browsers
    if(window.DOMParser) {
      var getxml = new DOMParser();
      var xmlDoc = getxml.parseFromString(xml,"text/xml");
    }
    else {
      // for Internet Explorer
      var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
      xmlDoc.async = "false";
    }

    // gets the JSON string
    var json_str = jsontoStr(setJsonObj(xmlDoc));

    // sets and returns the JSON object, if "rstr" undefined (not passed), else, returns JSON string
    return (typeof(rstr) == 'undefined') ? JSON.parse(json_str) : json_str;
  }

  // receives XML DOM object, returns converted JSON object
  var setJsonObj = function(xml) {
    var js_obj = {};
    if (xml.nodeType == 1) {
      if (xml.attributes.length > 0) {
        js_obj["@attributes"] = {};
        for (var j = 0; j < xml.attributes.length; j++) {
          var attribute = xml.attributes.item(j);
          js_obj["@attributes"][attribute.nodeName] = attribute.value;
        }
      }
    } else if (xml.nodeType == 3) {
      js_obj = xml.nodeValue;
    }            
    if (xml.hasChildNodes()) {
      for (var i = 0; i < xml.childNodes.length; i++) {
        var item = xml.childNodes.item(i);
        var nodeName = item.nodeName;
        if (typeof(js_obj[nodeName]) == "undefined") {
          js_obj[nodeName] = setJsonObj(item);
        } else {
          if (typeof(js_obj[nodeName].push) == "undefined") {
            var old = js_obj[nodeName];
            js_obj[nodeName] = [];
            js_obj[nodeName].push(old);
          }
          js_obj[nodeName].push(setJsonObj(item));
        }
      }
    }
    return js_obj;
  }

  // converts JSON object to string (human readable).
  // Removes '\t\r\n', rows with multiples '""', multiple empty rows, '  "",', and "  ",; replace empty [] with ""
  var jsontoStr = function(js_obj) {
    var rejsn = JSON.stringify(js_obj, undefined, 2).replace(/(\\t|\\r|\\n)/g, '').replace(/"",[\n\t\r\s]+""[,]*/g, '').replace(/(\n[\t\s\r]*\n)/g, '').replace(/[\s\t]{2,}""[,]{0,1}/g, '').replace(/"[\s\t]{1,}"[,]{0,1}/g, '').replace(/\[[\t\s]*\]/g, '""');
    return (rejsn.indexOf('"parsererror": {') == -1) ? rejsn : 'Invalid XML format';
  }
};

// creates object instance of XMLtoJSON
var xml2json = new XMLtoJSON();