map code

<script>
  		var directionsDisplay;
			var directionsService = new google.maps.DirectionsService();
			var map;

			function initialize() {
			  directionsDisplay = new google.maps.DirectionsRenderer();
			  var chicago = new google.maps.LatLng(41.850033, -87.6500523);
			  var mapOptions = {
				zoom: 6,
				mapTypeId: google.maps.MapTypeId.ROADMAP,
				center: chicago
			  }
			  map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
			  directionsDisplay.setMap(map);
			}

			function calcRoute() {
			  var start = document.getElementById("start").value;
			  var end = document.getElementById("end").value;
			  var waypts = [];
			  var checkboxArray = document.getElementById("waypoints");
			  for (var i = 0; i < checkboxArray.length; i++) {
				if (checkboxArray.options[i].selected == true) {
				  waypts.push({
					  location:checkboxArray[i].value,
					  stopover:true
				  });
				}
			  }

			  var request = {
				  origin: start,
				  destination: end,
				  waypoints: waypts,
				  optimizeWaypoints: true,
				  travelMode: google.maps.TravelMode.DRIVING
				};
			  
			  directionsService.route(request, function(response, status) {
				if (status == google.maps.DirectionsStatus.OK) {
				  directionsDisplay 
					= new google.maps
					.DirectionsRenderer({panel:document.getElementById('directions_panel')});
				  }
				});
			}
		</script>