color_marker.js

let map;
function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    center: {lat: -34.397, lng: 150.644},
    zoom: 8
  });

  let marker = new google.maps.Marker({
    map: map,
    position: {lat: -34.397, lng: 150.644},
    icon: {
      url: "http://maps.google.com/mapfiles/ms/icons/blue-dot.png"
    }
  });
}