JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://maps.googleapis.com/maps/api/js?v=3&amp;libraries=geometry"></script>
<div id="map_div" style="height: 400px;"></div>

CSS

#map_div {
			width: 600px; height: 400px; 
		}

JavaScript

/*
     * declare map as a global variable
     */
    var map;

    /*
     * use google maps api built-in mechanism to attach dom events
     */
    function initialize() {

      /*
       * create map
       */
      var map = new google.maps.Map(document.getElementById("map_div"), {
        center: new google.maps.LatLng(33.808678, -117.918921),
        zoom: 14,
        mapTypeId: google.maps.MapTypeId.ROADMAP
      });

      /*
       * create infowindow (which will be used by markers)
       */
      var infoWindow = new google.maps.InfoWindow();

      /*
       * marker creater function (acts as a closure for html parameter)
       */
      function createMarker(options, html) {
        var marker = new google.maps.Marker(options);
        if (html) {
          google.maps.event.addListener(marker, "click", function () {
            infoWindow.setContent(html);
            infoWindow.open(options.map, this);
          });
        }
        return marker;
      }

      /*
       * add markers to map
       */
      var marker0 = createMarker({
        position: new google.maps.LatLng(33.808678, -117.918921),
        map: map,
        icon: { url :  "http://1.bp.blogspot.com/_GZzKwf6g1o8/S6xwK6CSghI/AAAAAAAAA98/_iA3r4Ehclk/s1600/marker-green.png" }
      }, "<h1>Marker 0</h1><p>This is the home marker.</p>");

      var marker1 = createMarker({
        position: new google.maps.LatLng(33.818038, -117.928492),
        map: map
      }, "<h1>Marker 1</h1><p>This is marker 1</p>");

      var marker2 = createMarker({
        position: new google.maps.LatLng(33.803333, -117.915278),
        map: map
      }, "<h1>Marker 2</h1><p>This is marker 2</p>");
        
        setInterval(function(){ marker0.setIcon({ url :  "http://1.bp.blogspot.com/_GZzKwf6g1o8/S6xwK6CSghI/AAAAAAAAA98/_iA3r4Ehclk/s1600/marker-green.png" }); alert("called");}, 10000);
    }

initialize();