var map =new google.maps.Map(document.getElementById("map-canvas"), mapOptions);

google.maps.event.addListener(map, "rightclick", function(event) { var lat = event.latLng.lat(); var lng = event.latLng.lng();
var myLatlng =new google.maps.LatLng(lat ,lng );
var mapOptions ={
  zoom:4,
  center: myLatlng,
  mapTypeId: google.maps.MapTypeId.ROADMAP,
}


var marker =new google.maps.Marker({
    position: myLatlng,
    title:"Hello World!"
});

// To add the marker to the map, call setMap();
marker.setMap(map);
});