google maps get radius
===

I'm having a stupid hard time with this google maps javascript code. I want to get the return of the radius of a circle that is produced on google maps. Google API offers the code but I have no idea where to put it. I've tried everywhere. Here is the code below. What did I do wrong?


    <!DOCTYPE html>
    <html>
    <head>

    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">

    <meta charset="utf-8">

    <style type="text/css"> 
     html { height: 100% }
     body { height: 100%; margin: 0px; padding: 0px }
     #map_canvas { height: 50% }
    </style> 

    <script type="text/javascript"
      src="http://maps.googleapis.com/maps/api/js?key=mykey&sensor=false&libraries=drawing">
    </script>

    <script>
      function initialize() {
        var mapOptions = {
          center: new google.maps.LatLng(33.65, -84.42),
          zoom: 7,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        };

        var map = new google.maps.Map(document.getElementById('map_canvas'),
          mapOptions);

        var drawingManager = new google.maps.drawing.DrawingManager({
          drawingMode: google.maps.drawing.OverlayType.MARKER,
          drawingControl: true,
          drawingControlOptions: {
            position: google.maps.ControlPosition.TOP_CENTER,
            drawingModes: [

              google.maps.drawing.OverlayType.CIRCLE
            ]
          },
          
          circleOptions: {
            fillColor: '#01939A',
            fillOpacity: .4,
            strokeWeight: 5,
            clickable: false,
            editable: true,
            zIndex: 1
          }
        });
 

 
 
        drawingManager.setMap(map);
	    


   
    
 		 }

      google.maps.event.addDomListener(window, 'load', 

      initialize).addListener(drawingManager, 'circlecomplete', function(circle) 

      {
	
      var radius = circle.getRadius();
	
      });
  
    </script>

    </head>

    <body>

    <script type="text/javascript" >

			alert(radius);

    </script>


    <div id="map_canvas"></div>

    </body>

    </html>