Source: maybeathome.autocomplete [edit]

      <script>
      // This example displays an address form, using the autocomplete feature
      // of the Google Places API to help users fill in the information.

      // This example requires the Places library. Include the libraries=places
      // parameter when you first load the API. For example:
      // <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=places">

      var placeSearch, autocomplete;
      var componentForm = {
        street_number: 'short_name',
        route: 'long_name',
        locality: 'long_name',
        administrative_area_level_2: 'short_name',
        administrative_area_level_1: 'short_name',
        country: 'short_name',
        postal_code: 'short_name'
      };

      function initAutocomplete() {
        // Create the autocomplete object, restricting the search to geographical
        // location types.
        autocomplete = new google.maps.places.Autocomplete(
            /** @type {!HTMLInputElement} */(document.getElementById('address')),
            {types: ['geocode']});

        // When the user selects an address from the dropdown, populate the address
        // fields in the form.
        autocomplete.addListener('place_changed', fillInAddress);
      }

      function fillInAddress() {
        // Get the place details from the autocomplete object.
        var place = autocomplete.getPlace();

        for (var component in componentForm) {
          if (document.getElementById(component + "_hid")) {
             document.getElementById(component + "_hid").value = '';
             document.getElementById(component + "_hid").disabled = false;
          }
        }
        
        if (document.getElementById("lat_hid")) {
           document.getElementById("lat_hid").value = place.geometry.location.lat();
           document.getElementById("lng_hid").value = place.geometry.location.lng();
        }        

        // Get each component of the address from the place details
        // and fill the corresponding field on the form.
        for (var i = 0; i < place.address_components.length; i++) {
          var addressType = place.address_components[i].types[0];
          if (componentForm[addressType]) {
            var val = place.address_components[i][componentForm[addressType]];
            var fld = addressType + "_hid";
            if (document.getElementById(fld)) {
               document.getElementById(fld).value = val;
               console.log(fld + " = " + val);
            }
          }
        }
      }

      // Bias the autocomplete object to the user's geographical location,
      // as supplied by the browser's 'navigator.geolocation' object.
      function geolocate() {
        if (navigator.geolocation) {
          navigator.geolocation.getCurrentPosition(function(position) {
            var geolocation = {
              lat: position.coords.latitude,
              lng: position.coords.longitude
            };
            var circle = new google.maps.Circle({
              center: geolocation,
              radius: position.coords.accuracy
            });
            autocomplete.setBounds(circle.getBounds());
          });
        }
      }
      
    </script>

    <!-- script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAO2RntyX5IUgDJmXO-i39U06wwIhKwdEE&libraries=places&callback=initAutocomplete"
        async defer></script -->