Wordpress plugin does not display html

Question

I’m trying to make a simple plugin that show via shortcode a small google maps map with the current location of the user, but when I put the shortcode the map does not appear, follows the code:

function GetMyLocation(){

?>

<div id="map"></div>
<script>

  function initMap() {
    var map = new google.maps.Map(document.getElementById('map'), {
      center: {lat: -34.397, lng: 150.644},
      zoom: 6
    });
    var infoWindow = new google.maps.InfoWindow({map: map});

    // Try HTML5 geolocation.
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(function(position) {
        var pos = {
          lat: position.coords.latitude,
          lng: position.coords.longitude
        };

        infoWindow.setPosition(pos);
        infoWindow.setContent('Location found.');
        map.setCenter(pos);
      }, function() {
        handleLocationError(true, infoWindow, map.getCenter());
      });
    } else {
      // Browser doesn't support Geolocation
      handleLocationError(false, infoWindow, map.getCenter());
    }
  }

  function handleLocationError(browserHasGeolocation, infoWindow, pos) {
    infoWindow.setPosition(pos);
    infoWindow.setContent(browserHasGeolocation ?
                          'Error: The Geolocation service failed.' :
                          'Error: Your browser doesn\'t support geolocation.');
  }
</script>
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDn4VzI0_FK0rrbg0QHcLH0l-_n4eFoHnk&callback=initMap">
</script>