function initialize() { var myLatlng = new google.maps.LatLng(21.019845, 105.827122); var mapOptions = { zoom: 14, center: myLatlng } var contentString = ''; var infowindow = new google.maps.InfoWindow({ content: contentString }); var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions); var marker = new google.maps.Marker({ position: myLatlng, map: map, title: 'Hello World!' }); google.maps.event.addListener(marker, 'click', function() { infowindow.open(map, marker); }); } google.maps.event.addDomListener(window, 'load', initialize);