Google Version 3 Maps Geocoder, Get Coordinates of marker layer when clicking or dragging marker

问题

I have made a Google Version 3 Geocoder , I want to be able to pick up the coordinates of the marker when it is dragged or clicked. Below is my code:

<!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>Google Maps JavaScript API v3 Example: Geocoding Simple</title>
<link href="http://code.google.com/apis/maps/documentation/javascript/examples/default.css" rel="stylesheet" type="text/css" />
<script src="http://maps.google.com/maps/api/js?v=3.5&amp;sensor=false"></script>
<script type="text/javascript">
var geocoder;
var map;
function initialize() {
geocoder = new google.maps.Geocoder();
var latlng = new google.maps.LatLng(-34.397, 150.644);
var myOptions = {
  zoom: 8,
  center: latlng,
  mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
}


function codeAddress() {
var address = document.getElementById("address").value;
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,
        draggable: true,
        position: results[0].geometry.location

    });
  } else {
    alert("Geocode was not successful for the following reason: " + status);
  }
});
}
</script>

<style type="text/css">
#controls {
position: absolute;
bottom: 1em;
left: 100px;
width: 400px;
z-index: 20000;
padding: 0 0.5em 0.5em 0.5em;
}
 html, body, #map_canvas {
            margin: 0;
            width: 100%;
            height: 100%;
        }
</style>
</head>
<body onload="initialize()">
<div id="controls">
<input id="address" type="textbox" value="Sydney, NSW">

<input type="button" value="Geocode" onclick="codeAddress()">
</div>
<div id="map_canvas"></div>
</body>
</html>

I have tried to use the following code to do this but it does not seem to work.

       // Javascript//
       google.maps.event.addListener(marker, 'dragend', function(evt){
       document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
       });

       google.maps.event.addListener(marker, 'dragstart', function(evt){
       document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
       });

 map.setCenter(marker.position);
 marker.setMap(map);

 //HTML//
 <div id='map_canvas'></div>
 <div id="current">Nothing yet...</div>