如何用javascript在google map中动态画线?

var map;
function initialize() {
    var myLatlng = new google.maps.LatLng(0,-180);
    var myOptions = {
      zoom: 3,
      center: myLatlng,
      mapTypeId: google.maps.MapTypeId.ROADMAP       
    };
    map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
    var flightPlanCoordinates = [
                                 new google.maps.LatLng(37.772323, -122.214897),
                                 new google.maps.LatLng(28.213356,112.977046),
                                 new google.maps.LatLng(21.291982, -157.821856),
                                 new google.maps.LatLng(-18.142599, 178.431),
                                 new google.maps.LatLng(-27.46758, 153.027892)
                               ];
                               var flightPath = new google.maps.Polyline({
                                 path: flightPlanCoordinates,
                                 strokeColor: "#FF0000",
                                 strokeOpacity: 1.0,
                                 strokeWeight: 2
                               });

                               flightPath.setMap(map);
                             }

这个是画线的代码···你加了事件监听就OK了···