Insert data dynamically with xml the coordinates in the heat map

Question

I’m trying to use this code to read the coordinates data xml instead of the statically inserted data in the code but it doesn’t work when done this way. Code:

function getPoints() {
  return [
                //new google.maps.LatLng(-26.20478566666, -51.0518355),                 
                //new google.maps.LatLng(-26.265426, -51.10279483333),
                //  new google.maps.LatLng(-26.265426, -51.10279483333),                    
                //  new google.maps.LatLng(-26.22920166666, -51.08537583333),
                //  new google.maps.LatLng(-26.21230783333, -51.0784765),
                //  new google.maps.LatLng(-26.21460016666,-51.07964916666),
                //  new google.maps.LatLng(-26.21396566666, -51.076862),
                //  new google.maps.LatLng(-26.23305616666, -51.05080116666),
                //  new google.maps.LatLng(-26.2335205, -51.05153366666),
                //  new google.maps.LatLng(-26.22982933333, -51.08531783333),
                //  new google.maps.LatLng(-26.20052716666, -51.09534966666),
                //  new google.maps.LatLng(-26.22196833333, -51.05161116666),
                //  new google.maps.LatLng(-26.20052716666, -51.09534966666),
                //  new google.maps.LatLng(-26.22196833333, -51.05161116666),
                //  new google.maps.LatLng(-26.22650916666, -51.08625616666),
                //  new google.maps.LatLng(-26.22650916666, -51.08625616666),
                //  new google.maps.LatLng(-26.22196833333, -51.05161116666),                   
                //  new google.maps.LatLng(-26.22650916666, -51.08625616666)

                    downloadUrl("dados.xml", function(data) 
                    {
                        var xml = data.responseXML;
                        var markers = xml.documentElement.getElementsByTagName("marker");
                        for (var i = 0; i < markers.length; i++) 
                        {                     
                             var point = new google.maps.LatLng
                             (
                              parseFloat(markers[i].getAttribute("lat")),
                              parseFloat(markers[i].getAttribute("lng"))
                              );                    
                        };              
                    }
                    );
  ];
}
function downloadUrl(url, callback) {
              var request = window.ActiveXObject ?
                  new ActiveXObject('Microsoft.XMLHTTP') :
                  new XMLHttpRequest;

              request.onreadystatechange = function() {
                if (request.readyState == 4) {
                  request.onreadystatechange = doNothing;
                  callback(request, request.status);
                }
              };

              request.open('GET', url, true);
              request.send(null);

The implementation I’m using is based on this example https://developers.google.com/maps/documentation/javascript/heatmaplayer?hl=pt-br#load_the_visualization_library