Add marker to existing google map (without refresh google map) [duplicate]

Answer 1

Yes. When you added your markers originally, your probably did something like:

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

The map already existed (map: map), and you added markers. You can do the same thing later to add more markers.

Answer 2

var latlng = new google.maps.LatLng(42.745334, 12.738430);

function addmarker(latilongi) {
    var marker = new google.maps.Marker({
        position: latilongi,
        title: 'new marker',
        draggable: true,
        map: map
    });
    map.setCenter(marker.getPosition())
}

$('#btnaddmarker').on('click', function() {
    addmarker(latlng)
})