mapApp.html

<!DOCTYPE html>
<html>

  <head><title> ADS-B Map </title>
    <meta name="viewport"
      content="initial-scale=1.0, user-scalable=no" />
    <style type="text/css">
      html { height: 100% }
      body { height: 100%; margin: 0; padding: 0 }
      #mapDiv {
        height: 400px; width: 100%; }
    </style>
    <script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key=AIzaSyBZ4ClMwcXBcfO3_bqQPTvryxi5GZN7g0I">
    </script>
    <script src='mapApp.js'></script>
  </head>
  <body>
    <h3>Google Map Test</h3>
    <div id="mapDiv"></div>
    <button id="btnTerrain">Terrain</button>
    <button id="btnRoadmap">Roadmap</button>
    <button id="btnSatellite">Satellite</button>
    <button id="btnHybrid">Hybrid</button>
  </body>
</html>