How to control google map markers' opacity

Question

I need to make some markers semi-transparent depending on time. Is there any way to control the CSS opacity of a marker? Or is it possible to reliably find out a marker's DOM element?

I use Google Maps API v3.

Answer 1

The opacity of markers can be set with marker.setOptions({'opacity': 0.5})

Answer 2

You can use marker.setOpacity(0.5); https://developers.google.com/maps/documentation/javascript/3.exp/reference#Marker

code snippet:

var marker;

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      zoom: 10,
      center: {
        lat: -33.9,
        lng: 151.2
      },
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  marker = new google.maps.Marker({
    position: {
      lat: -33.890542,
      lng: 151.274856
    },
    map: map,
    title: "Bondi Beach"
  });
}
google.maps.event.addDomListener(window, "load", initialize);

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<input id="inc" type="text" value="0.5" />
<input type="button" id="set" value="set opacity" onclick="marker.setOpacity(parseFloat(document.getElementById('inc').value))" />
<input type="button" id="full" value="full opacity" onclick="marker.setOpacity(1.0);" />
<div id="map_canvas"></div>