Place a new marker and update fields in a form with gmaps4rails

gistfile1.rhtml

	<%= gmaps4rails(@json) %>
	<% content_for :scripts do %>
		<script type="text/javascript" charset="utf-8">
			var markersArray = [];
			// On click, clear markers, place a new one, update coordinates in the form
			Gmaps.map.callback = function() {
				google.maps.event.addListener(Gmaps.map.map, 'click', function(event) {
				  clearOverlays();
				  placeMarker(event.latLng);
				  updateFormLocation(event.latLng);
				});
			};
			// Update form attributes with given coordinates
			function updateFormLocation(latLng) {
				$('location_attributes_latitude_str').value = latLng.lat();
				$('location_attributes_longitude_str').value = latLng.lng();
				$('location_attributes_gmaps_zoom').value = Gmaps.map.map.getZoom();
			}
			// Add a marker with an open infowindow
			function placeMarker(latLng) {
				var marker = new google.maps.Marker({
				    position: latLng, 
				    map: Gmaps.map.map,
				    draggable: true
				});
				markersArray.push(marker);
				// Set and open infowindow
				var infowindow = new google.maps.InfoWindow({
				    content: '<div class="popup"><h2>Awesome!</h2><p>Drag me and adjust the zoom level.</p>'
				});
			  	infowindow.open(Gmaps.map.map,marker);
				// Listen to drag & drop
				google.maps.event.addListener(marker, 'dragend', function() {
					updateFormLocation(this.getPosition());
				});
			}
			// Removes the overlays from the map
			function clearOverlays() {
			  if (markersArray) {
			    for (var i = 0; i < markersArray.length; i++ ) {
			      markersArray[i].setMap(null);
			    }
			  }
			  markersArray.length = 0;
			}
		</script>
	<% end %>