set marker one by one on map from database

See more:

C#

ASP.NET

i have following code which plot all marker at same time on map...
but i want to plot those marker after some time interval like 2 or 5 second..
give me some idea..
Thank you !!!

Here is my code...

map.aspx page :

<script src="http://maps.google.com/maps/api/js?sensor=false" 
          type="text/javascript"></script>
          
  <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false&v=3&libraries=geometry"></script>
  <script type="text/javascript" charset="UTF-8" src="http://maps.gstatic.com/intl/en_ALL/mapfiles/400d/maps2.api/mod_api_gc.js"></script>
 <script type="text/javascript">
        
        
    var locations = [<%=data%>];
        
    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 15,
      center: new google.maps.LatLng(<%=slat%>, <%=slong%>),
      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]),
        animation: google.maps.Animation.DROP,
        map: map
       
      });
      
      google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() {
          infowindow.setContent(locations[i][0]);
          infowindow.open(map, marker);
        }
      })(marker, i));
    }
  </script>

map.aspx.cs page :

protected void Page_Load(object sender, EventArgs e)
    {
        SqlDataAdapter adp = new SqlDataAdapter("select lat,long from data", con);
        DataTable dt = new DataTable();
        adp.Fill(dt);
        if (dt.Rows.Count > 0)
        {
            int cnt = dt.Rows.Count;
            int j = dt.Rows.Count / 2;
            slat = dt.Rows[j]["lat"].ToString();
            slong = dt.Rows[j]["long"].ToString();

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                
                data += "['navsari'," + dt.Rows[i]["lat"].ToString() + "," + dt.Rows[i]["long"].ToString() + "]";
                data += ",";
            }
        }

        data = data.TrimEnd(',');
}