cannot parse a url from xml file in javascript

Question

I'm trying to parse an xml file . I'm using the function downloadUrl . The element <link> of my xml file contains a url with ' & ' ( ampersant character ) . The error in my browser says : " Cannot read property 'documentElement' of null " I replace the & with & in a sample file-similar to my xml and the parse runs great!One important information : I cannot edit my xml file . So , the solution is to insert at the javascript code a function to replace this character & with & .Something like that i imagine:

function htmlEscape(items) {
    return String(items)
            .replace(/&/g, '&');
    }

But i cannot find the way on how to do that. Here's is my script :

var infowindow;
      var map;

      function initialize() {
        var myLatlng = new google.maps.LatLng(38.822590,24.653320);
        var myOptions = {
          zoom: 6,
          center: myLatlng,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        }
        map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
        downloadUrl("moredata.xml", function(doc) {
          var items = doc.documentElement.getElementsByTagName("item");
          for (var i = 0; i < items.length; i++) {
               var description = items[i].getElementsByTagName("description")[0].textContent;
                var temp        = items[i].getElementsByTagName("temp")[0].textContent;
                    var title       = items[i].getElementsByTagName("title")[0].textContent;
            var link        = items[i].getElementsByTagName("link")[0].textContent;
            var latlng      = new google.maps.LatLng(parseFloat(items[i].getElementsByTagName("glat")[0].textContent),
                                                     parseFloat(items[i].getElementsByTagName("glon")[0].textContent));

a part of my xml :

<channel>
    <title>
        Real time weather in Greece
    </title>
    <link>http://www.123.gr/</link>
    <image>
    <url>
    http://www.123.gr/templates/metar/images/metar.gif
    </url>
    <title>123.gr</title>
    <link>http://www.123.gr/</link>
    </image>
    <description>
    Real time weather in Greece
    </description>
    <language>el</language>
    <pubDate>Thu, 03 Apr 2014 17:08:10 +0300</pubDate>
    <copyright>123.gr</copyright>
    <managingEditor>kondilis@123.gr</managingEditor>
    <webMaster>admin@123.gr</webMaster>
    <item>
    <title>Center</title>
    <description>Salonica</description>
    <link>
        http://www.metar.gr/index.php?option=com_jumi&fileid=12&Itemid=73&station=1227
    </link>
    <temp>16.7 °C</temp>
    <glat>40.422726139672626</glat>
    <glon>22.93392777442932</glon>
    </item>
</channel>

the downloadUrl function :

function downloadUrl(url, callback) {
 var status = -1;
 var request = createXmlHttpRequest();
 if (!request) {
   return false;
 }

 request.onreadystatechange = function() {
   if (request.readyState == 4) {
     try {
       status = request.status;
     } catch (e) {
       // Usually indicates request timed out in FF.
     }
     if (status == 200) {
       callback(request.responseXML, request.status);
       request.onreadystatechange = function() {};
     }
   }
 }
 request.open('GET', url, true);
 try {
   request.send(null);
 } catch (e) {
   changeStatus(e);
 }
};

Answer 1

The problem is that responseXML is broken because of an invalid XML document, it's not just an invalid string. You will probably have to retrieve the responseText , replace the ampersands with properly encoded entities and then do something like the solutions to this SO question to make that string into a traversable XML document