<script type="text/javascript">

  var markerCluster = null;

  var map;

  var listener;

function initialize() {

  var mapOptions = {

    zoom: 10,

            center: new google.maps.LatLng(23.56, 120.56247),

          mapTypeId: google.maps.MapTypeId.ROADMAP

  };

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

google.maps.event.addListener(map, 'dragstart', onDragstart);

google.maps.event.addListener(map, 'dragend', onDragend);

listener = google.maps.event.addListener(map, 'bounds_changed', onBounds_changed);  

 }

function onDragstart(){

  google.maps.event.removeListener(listener);

  }

  function onDragend(){

  listener = google.maps.event.addListener(map, 'bounds_changed', onBounds_changed); 

  }

var timeout;

  function onBounds_changed(){

window.clearTimeout(timeout);

timeout = window.setTimeout(function() {

var bounds = map.getBounds();

  $("#boundinfo").text('坐標：'+bounds.getSouthWest()+','+bounds.getNorthEast());

}, 2000);

  }

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