silphire/index.html

## index.html
<html lang="ja">                                                                  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <title>test</title>
    <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
    <script type="text/javascript" src="map.js"></script>
  </head>

  <body onload="initialize()">
    <div id="control" style="width: 100%; height: 10%">
      <input type="button" value="clear" onclick="clear_markers()">
    </div>

    <div id="main_map" style="width: 100%; height: 80%">
    </div>
  </body>
</html>

## map.js
var theMap;
var directionsService = new google.maps.DirectionsService();
var directionsDisplay;
var markers = [];
var wayPoints = [];

function initialize() {
  var myOptions = {
    zoom: 8,
    center: new google.maps.LatLng(35.65, 139.75),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };

  directionsDisplay = new google.maps.DirectionsRenderer();
  theMap = new google.maps.Map(document.getElementById("main_map"), myOptions);
  directionsDisplay.setMap(theMap);

  google.maps.event.addListener(theMap, 'click', function(ev) {
    // マーカー表示
    var newMarker = new google.maps.Marker({
      position: ev.latLng,
      draggable: false,
      map: theMap
    });
    markers.push(newMarker);

    if(markers.length > 2) {
      wayPoints.push(ev.latLng);
    }

    if(markers.length >= 2) {
      var request = {
	origin: markers[0].position,
	destination: markers[markers.length - 1].position,
	waypoints: wayPoints,
	travelMode: google.maps.DirectionsTravelMode.WALKING,
	unitSystem: google.maps.DirectionsUnitSystem.METRIC
      };

      directionsService.route(request, function(result, status) {
	if(status == google.maps.DirectionsStatus.OK) {
	  directionsDisplay.setDirections(result);
	}
      });
    }
  });
}

function clear_markers() {
}
	<html lang="ja"> <head>
	<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
	<title>test</title>
	<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
	<script type="text/javascript" src="map.js"></script>
	</head>

	<body onload="initialize()">
	<div id="control" style="width: 100%; height: 10%">
	<input type="button" value="clear" onclick="clear_markers()">
	</div>

	<div id="main_map" style="width: 100%; height: 80%">
	</div>
	</body>
	</html>
	var theMap;
	var directionsService = new google.maps.DirectionsService();
	var directionsDisplay;
	var markers = [];
	var wayPoints = [];

	function initialize() {
	var myOptions = {
	zoom: 8,
	center: new google.maps.LatLng(35.65, 139.75),
	mapTypeId: google.maps.MapTypeId.ROADMAP
	};

	directionsDisplay = new google.maps.DirectionsRenderer();
	theMap = new google.maps.Map(document.getElementById("main_map"), myOptions);
	directionsDisplay.setMap(theMap);

	google.maps.event.addListener(theMap, 'click', function(ev) {
	// マーカー表示
	var newMarker = new google.maps.Marker({
	position: ev.latLng,
	draggable: false,
	map: theMap
	});
	markers.push(newMarker);

	if(markers.length > 2) {
	wayPoints.push(ev.latLng);
	}

	if(markers.length >= 2) {
	var request = {
	origin: markers[0].position,
	destination: markers[markers.length - 1].position,
	waypoints: wayPoints,
	travelMode: google.maps.DirectionsTravelMode.WALKING,
	unitSystem: google.maps.DirectionsUnitSystem.METRIC
	};

	directionsService.route(request, function(result, status) {
	if(status == google.maps.DirectionsStatus.OK) {
	directionsDisplay.setDirections(result);
	}
	});
	}
	});
	}

	function clear_markers() {
	}