单击 POI 时获取谷歌地图上的 placeId

function initialize() {
  var mapOptions = {
    zoom: 14,
    center: new google.maps.LatLng(38.8862447, -77.02158380000003),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };
  map = new google.maps.Map(document.getElementById('map_canvas'),
    mapOptions);

  geocoder = new google.maps.Geocoder;

  //keep a reference to the original setPosition-function
  var fx = google.maps.InfoWindow.prototype.setPosition;

  //override the built-in setPosition-method
  google.maps.InfoWindow.prototype.setPosition = function() {

    //this property isn't documented, but as it seems
    //it's only defined for InfoWindows opened on POI's
    if (this.logAsInternal) {
      google.maps.event.addListenerOnce(this, 'map_changed', function() {
        var map = this.getMap();

        //the infoWindow will be opened, usually after a click on a POI
        if (map) {

          //trigger the click
          google.maps.event.trigger(map, 'click', {
            latLng: this.getPosition()
          });
        }
      });
    }
    //call the original setPosition-method
    fx.apply(this, arguments);
  };

  google.maps.event.addListener(map, 'click', function(e) {
    //alert('clicked @' + e.latLng.toString())
    geocoder.geocode({
      'location': e.latLng
    }, function(results, status) {
      if (status === google.maps.GeocoderStatus.OK) {
        if (results[0]) {

          alert('place id: ' + results[0].place_id);


        } else {
          console.log('No results found');
        }
      } else {
        console.log('Geocoder failed due to: ' + status);
      }
    });

  });
}

google.maps.event.addDomListener(window, 'load', initialize);

html,
body,
#map_canvas {
  margin: 0;
  height: 100%;
}

<div id="map_canvas"></div>
<script src="https://maps.googleapis.com/maps/api/js?callback=initialize" async defer></script>