title: Update marker in real time
body: <p>I need fetch the new position from json file which will be updated at  regualr   intervals in order to update it on the map without reloading the whole page repeatedly.  How can I do without using Ajax</p>
  
  <pre><code>                 if (GBrowserIsCompatible()) {
                   //==add controls
                   var map = new GMap(document.getElementById("map"));
                   map.addControl(new GLargeMapControl());
                   map.addControl(new GMapTypeControl());
                   map.setCenter(new GLatLng(-29.870879, 30.977258),15);
  
                   var htmls = [];
                   var i = 0;
  
                   //create marker and set up infoWindow
                   function createMarker(point,ID,name) {
                   var marker = new GMarker(point);
                   GEvent.addListener(marker, "click", function() {
                   marker.openInfoWindowHtml(ID+"&lt;br/&gt;Name: " +name);
  
                   });
  
                    return marker;
                  }
  
  
  
              process_Data = function(doc) {
                   //parse json file
                   var jsonData = eval('(' + doc + ')');
  
                   // ======== Plots the markers on Google Maps============
  
                     for (var i=0; i&lt;jsonData.markers.length; i++) {
                         var point = new GLatLng(jsonData.markers[i].lat, jsonData.markers[i].lng);
                          var marker = createMarker(point,jsonData.markers[i].ID,jsonData.markers[i].name);
                         map.addOverlay(marker);
  
                         }
                       }
  
                        GDownloadUrl("points.json", process_Data);
  
                        }
  </code></pre>