Google map: percorso tra 2 punti in Km

[Vindav]

var service = new google.maps.DistanceMatrixService();
var request = {
	      origins:[new google.maps.LatLng(45.468945,9.181030)],
	      destinations:[new google.maps.LatLng(41.903110,12.495760),new google.maps.LatLng(45.190825, 9.150414)],
	      travelMode: google.maps.TravelMode.DRIVING,
	      unitSystem: google.maps.UnitSystem.METRIC
      };
      service.getDistanceMatrix(request, function(result, status){
		if (status == google.maps.DistanceMatrixStatus.OK) {
			for(i=0;i<result.rows.length;i++){
				for(j=0;j<result.rows[i].elements.length;j++){
					alert(result.rows[i].elements[j].distance.text);
				}
			}
      	}
      });