Data Layer: Event Handling

View this example full screen.

JavaScript

var map;
function initialize() {
  map = new google.maps.Map(document.getElementById('map-canvas'), {
    zoom: 4,
    center: {lat: -28, lng: 137.883}
  });

  // Load GeoJSON.
  map.data.loadGeoJson('https://storage.googleapis.com/maps-devrel/google.json');

  // Add some style.
  map.data.setStyle(function(feature) {
    return /** @type {google.maps.Data.StyleOptions} */({
      fillColor: feature.getProperty('color'),
      strokeWeight: 1
    });
  });

  // Set mouseover event for each feature.
  map.data.addListener('mouseover', function(event) {
    document.getElementById('info-box').textContent =
        event.feature.getProperty('letter');
  });
}

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

JavaScript + HTML

<!DOCTYPE html>
<html>
  <head>
    <title>Data Layer: Event Handling</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      html, body, #map-canvas {
        height: 100%;
        margin: 0px;
        padding: 0px
      }
    #info-box {
      background-color: white;
      border: 1px solid black;
      bottom: 30px;
      height: 20px;
      padding: 10px;
      position: absolute;
      left: 30px;
    }
    </style>
    <script src="https://maps.googleapis.com/maps/api/js?v=3.exp&signed_in=true"></script>
    <script>
var map;
function initialize() {
  map = new google.maps.Map(document.getElementById('map-canvas'), {
    zoom: 4,
    center: {lat: -28, lng: 137.883}
  });

  // Load GeoJSON.
  map.data.loadGeoJson('https://storage.googleapis.com/maps-devrel/google.json');

  // Add some style.
  map.data.setStyle(function(feature) {
    return /** @type {google.maps.Data.StyleOptions} */({
      fillColor: feature.getProperty('color'),
      strokeWeight: 1
    });
  });

  // [START snippet]
  // Set mouseover event for each feature.
  map.data.addListener('mouseover', function(event) {
    document.getElementById('info-box').textContent =
        event.feature.getProperty('letter');
  });
  // [END snippet]
}

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

    </script>
  </head>
  <body>
    <div id="map-canvas"></div>
    <div id="info-box">?</div>
  </body>
</html>