var geocoder;
var directionDisplay;
var directionsService = new google.maps.DirectionsService();
var map;

function initialize() {
  directionsDisplay = new google.maps.DirectionsRenderer();
  geocoder = new google.maps.Geocoder();
  var latlng = new google.maps.LatLng(-34.397, 150.644);
  var myOptions = {
    zoom: 12,
    center: latlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }
  map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
  directionsDisplay.setMap(map);
  directionsDisplay.setPanel(document.getElementById("directionsPanel"));
}

function codeAddress() {
  var address = document.getElementById("ToAddress").value;
  if (geocoder) {
    geocoder.geocode( {
      'address': address
    }, function(results, status) {
      if (status == google.maps.GeocoderStatus.OK) {
        map.setCenter(results[0].geometry.location);
        var marker = new google.maps.Marker({
          map: map,
          position: results[0].geometry.location
        });
      } else {
        alert("Geocode was not successful for the following reason: " + status);
      }
    });
  }
}

function calcRoute() {
  var start = document.getElementById("FromAddress").value;
  var end = document.getElementById("ToAddress").value;
  var request = {
    origin:start,
    destination:end,
    travelMode: google.maps.DirectionsTravelMode.DRIVING
  };
  directionsService.route(request, function(response, status) {
    if (status == google.maps.DirectionsStatus.OK) {
      directionsDisplay.setDirections(response);
    }
  });
}