Marker Animations With setTimeout()

This example uses window.setTimeout() to place markers on the map consecutively rather than all at once when a Drop Markers button is clicked.

Read the documentation.

// If you're adding a number of markers, you may want to drop them on the map
// consecutively rather than all at once. This example shows how to use
// window.setTimeout() to space your markers' animation.

var neighborhoods = [
  {lat: 52.511, lng: 13.447},
  {lat: 52.549, lng: 13.422},
  {lat: 52.497, lng: 13.396},
  {lat: 52.517, lng: 13.394}
];

var markers = [];
var map;

function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 12,
    center: {lat: 52.520, lng: 13.410}
  });
}

function drop() {
  clearMarkers();
  for (var i = 0; i < neighborhoods.length; i++) {
    addMarkerWithTimeout(neighborhoods[i], i * 200);
  }
}

function addMarkerWithTimeout(position, timeout) {
  window.setTimeout(function() {
    markers.push(new google.maps.Marker({
      position: position,
      map: map,
      animation: google.maps.Animation.DROP
    }));
  }, timeout);
}

function clearMarkers() {
  for (var i = 0; i < markers.length; i++) {
    markers[i].setMap(null);
  }
  markers = [];
}
<div id="floating-panel">
  <button id="drop" onclick="drop()">Drop Markers</button>
</div>
<div id="map"></div>
/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
#floating-panel {
  position: absolute;
  top: 10px;
  left: 25%;
  z-index: 5;
  background-color: #fff;
  padding: 5px;
  border: 1px solid #999;
  text-align: center;
  font-family: 'Roboto','sans-serif';
  line-height: 30px;
  padding-left: 10px;
}
#floating-panel {
  margin-left: -52px;
}
<!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap">
</script>

Try it yourself

You can experiment with this code in JSFiddle by clicking the <> icon in the top-right corner of the code window.

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Marker Animations With setTimeout()</title>
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
      #floating-panel {
        position: absolute;
        top: 10px;
        left: 25%;
        z-index: 5;
        background-color: #fff;
        padding: 5px;
        border: 1px solid #999;
        text-align: center;
        font-family: 'Roboto','sans-serif';
        line-height: 30px;
        padding-left: 10px;
      }
      #floating-panel {
        margin-left: -52px;
      }
    </style>
  </head>
  <body>
    <div id="floating-panel">
      <button id="drop" onclick="drop()">Drop Markers</button>
    </div>
    <div id="map"></div>
    <script>

      // If you're adding a number of markers, you may want to drop them on the map
      // consecutively rather than all at once. This example shows how to use
      // window.setTimeout() to space your markers' animation.

      var neighborhoods = [
        {lat: 52.511, lng: 13.447},
        {lat: 52.549, lng: 13.422},
        {lat: 52.497, lng: 13.396},
        {lat: 52.517, lng: 13.394}
      ];

      var markers = [];
      var map;

      function initMap() {
        map = new google.maps.Map(document.getElementById('map'), {
          zoom: 12,
          center: {lat: 52.520, lng: 13.410}
        });
      }

      function drop() {
        clearMarkers();
        for (var i = 0; i < neighborhoods.length; i++) {
          addMarkerWithTimeout(neighborhoods[i], i * 200);
        }
      }

      function addMarkerWithTimeout(position, timeout) {
        window.setTimeout(function() {
          markers.push(new google.maps.Marker({
            position: position,
            map: map,
            animation: google.maps.Animation.DROP
          }));
        }, timeout);
      }

      function clearMarkers() {
        for (var i = 0; i < markers.length; i++) {
          markers[i].setMap(null);
        }
        markers = [];
      }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
  </body>
</html>