google maps api V3で複数のマーカーを描画する #JavaScript

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<title></title>
<link href="http://code.google.com/apis/maps/documentation/javascript/examples/default.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
<script type="text/javascript">
  function render() {
    var rows = $("#data").val().split("\n");
    var latlng = new google.maps.LatLng(0,0);
    var cnt = 1;
    var options = {
      zoom: 4,
      center: latlng,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    var map = new google.maps.Map(document.getElementById("map_canvas"), options);

    $.each(rows, function() {
      var d = this.split(",");
      latlng = new google.maps.LatLng(d[1],d[0]);
      if(cnt == 1) {
        map.setCenter(latlng);
      }
      /* V3では map.addOverlay(marker) は使わないらしい */
      var marker = new google.maps.Marker({
        position: latlng, 
        map: map,
      });
      cnt++;
    });
  }
</script>
</head>
<body>
  <textarea id="data" cols="80" rows="10">
141.3478394,43.0583725,61.24,Thu Jun 09 18:12:29 2011
142.3478394,43.0583725,61.24,Thu Jun 09 18:12:29 2011
143.3478394,43.0583725,61.24,Thu Jun 09 18:12:29 2011
  </textarea>
  <input type="button" value="submit" onclick="render();" />
  <div id="map_canvas"></div>
</body>
</html>