Marker Clusterer for Google MAP API

CSS :

<style>

        html, body, form {

            margin: 0;

            font-family: Arial;

            font-size: 16px;

            height: 100%;

            width: 100%;

        }

        #map {

            height: 90%;

            width: 100%;

        }

    </style>

Add google MAp API link here and also Markerdata.JS

<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?v=3.exp"></script>

<script src="script/data.js"></script>

<script src="script/markerdata.js"></script>

Write Below JS code in your Page

var markers = [];

        var markerCluster

        function initialize() {

            var center = new google.maps.LatLng(37.4419, -122.1419);

            var map = new google.maps.Map(document.getElementById('map'), {

                zoom: 3,

                center: center,

                mapTypeId: google.maps.MapTypeId.ROADMAP

            });

            for (var i = 0; i < data.length; i++) {

                var latLng = new google.maps.LatLng(data[i].latitude, data[i].longitude);

                var marker = new google.maps.Marker({

                    position: latLng

                });

                markers.push(marker);

            }

            markerCluster = new MarkerClusterer(map, markers, { gridSize: 20 });

        }

        google.maps.event.addDomListener(window, 'load', initialize);

        function RemoveMarker() {

            var temp = '1'; // Will remove first marker from Array

            if (markerCluster != undefined) {

                if (markerCluster.removeMarker(markers[parseInt(temp.value)]))

                    markers.splice(parseInt(temp.value), 1);

            }

        }

        function AddMarker() {

            var latLng = new google.maps.LatLng(37.4419, -122.1419);

            var marker = new google.maps.Marker({

                position: latLng

            });

            if (markerCluster.addMarker(marker))

                markers.push(marker)

        }

Add Below HTML

  <div id="map"></div>

   <div>

            <input type="text" id="txt" />

            <input type="button" value="remove" id="btn" onclick="RemoveMarker();" />

   </div>

Download sample from Here
Output will like below.