You're all set!

To start developing, please head over to our developer documentation.

Activate the Google Maps JavaScript API

To get you started we'll guide you through the Google Developers Console to do a few things first:

  1. Create or choose a project
  2. Activate the Google Maps JavaScript API and related services
  3. Create appropriate keys
Continue

Data Layer: Event Handling

Read the documentation or view this example fullscreen.

var map;
function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 4,
    center: {lat: -28, lng: 137}
  });

  // 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');
  });
}
<div id="map"></div>
<div id="info-box">?</div>
/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
#info-box {
  background-color: white;
  border: 1px solid black;
  bottom: 30px;
  height: 20px;
  padding: 10px;
  position: absolute;
  left: 30px;
}
<!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap">
</script>

Try it yourself

Hover at top right of the code block to copy the code or open it in JSFiddle.

<!DOCTYPE html>
<html>
  <head>
    <title>Data Layer: Event Handling</title>
    <meta name="viewport" content="initial-scale=1.0">
    <meta charset="utf-8">
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
      #info-box {
        background-color: white;
        border: 1px solid black;
        bottom: 30px;
        height: 20px;
        padding: 10px;
        position: absolute;
        left: 30px;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <div id="info-box">?</div>
    <script>

      var map;
      function initMap() {
        map = new google.maps.Map(document.getElementById('map'), {
          zoom: 4,
          center: {lat: -28, lng: 137}
        });

        // 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');
        });
      }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
  </body>
</html>

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Google Maps JavaScript API
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