Hbs and google map

Why is map not showing in Hbs? I did research, but still nothing. Here is my code from template and style.css

index.hbs:

<div id="map"></div>
<script>
  function initMap() {
    var uluru = {lat: -25.363, lng: 131.044};
    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 4,
      center: uluru
    });
    var marker = new google.maps.Marker({
      position: uluru,
      map: map
    });
  }
</script>
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=My_API_KEY&callback=initMap">
</script>

css file:

#map {
    height: 400px;
    width: 100%;
   }

via perija