Google Maps: Marker inside circle?

Check if a marker is inside a circle with native google Maps API v3 methods

HTML

<script src="http://maps.googleapis.com/maps/api/js?sensor=false&amp;extension=.js"></script>
<div id="map" style="width:500px;height:500px;"></div>

JavaScript

var locations = [	
['Bondi Beach', -33.890542, 151.274856, 'http://www.destination360.com/australia-south-pacific/australia/images/s/australia-bondi-beach.jpg'],
	/*
	add more locations here on the form :
	[ name, lat, long, img ]
	[ name, lat, long, img ]
	..
	*/
];

function initialize() {
	var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 7,
          center: new google.maps.LatLng(-33.890542, 151.274856),
          mapTypeId: google.maps.MapTypeId.ROADMAP,
	});

	var infowindow = new google.maps.InfoWindow();
	var marker, i;

	for (i = 0; i < locations.length; i++) {  
	    marker = new google.maps.Marker({
    	    position: new google.maps.LatLng(locations[i][1], locations[i][2]),
			map: map
		});

		google.maps.event.addListener(marker, 'click', (function(marker, i) {
			return function() {
				var content=locations[i][0]+'<br><img src="'+locations[i][3]+'" style="width:300px;">';
				infowindow.setContent(content);
				infowindow.open(map, marker);
			}
		})(marker, i));
	}
}
google.maps.event.addDomListener(window, 'load', initialize);