How to change color in heatmap api google calender

In one of my projects, I have a google map setup with heatmap api in google and as with databases, I need to change the color of the heatmap. can anyone help me on this. my script

      <script type="text/javascript">
        var locations = [
          ['Bondi Beach', -33.890542, 151.274856, 4],
          ['Coogee Beach', -33.923036, 151.259052, 5],
          ['Cronulla Beach', -34.028249, 151.157507, 3],
          ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
          ['Maroubra Beach', -33.950198, 151.259302, 1]
        ];

        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 10,
          center: new google.maps.LatLng(-33.92, 151.25),
          mapTypeId: google.maps.MapTypeId.ROADMAP
        });
        var infowindow = new google.maps.InfoWindow();
        var marker, i;
        for (i = 0; i < locations.length; i++) {  
          marker = new google.maps.Marker({
            position: new google.maps.LatLng(locations[i][1], locations[i][2]),
            map: map
          });
          google.maps.event.addListener(marker, 'click', (function(marker, i) {
            return function() {
              infowindow.setContent(locations[i][0]);
              infowindow.open(map, marker);
            }
          })(marker, i));
        }
      </script>