# GMaps.js — Geofences

You can attach a geofence (which can be a polygon or a bounds) to a marker with:

    polygon = map.drawPolygon({
      paths: path,
      strokeColor: '#BBD8E9',
      strokeOpacity: 1,
      strokeWeight: 3,
      fillColor: '#BBD8E9',
      fillOpacity: 0.6
    });
    map.addMarker({
      lat: -12.043333,
      lng: -77.028333,
      draggable: true,
      fences: [polygon],
      outside: function(marker, fence){
        alert('This marker has been moved outside of its fence');
      }
    });

You must define an outside callback, which will use this `marker` and its `fence`.

Note: You also can use `checkMarkerGeofence` or `checkGeofence` methods.