Google Maps JS API v3 - Simple Multiple Marker Example

Here is another example of multiple markers loading with a unique title and infoWindow text. Tested with the latest google maps API V3.11.

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
        <title>Multiple Markers Google Maps</title>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
        <script src="https://maps.googleapis.com/maps/api/js?v=3.11&sensor=false" type="text/javascript"></script>
        <script type="text/javascript">
        // check DOM Ready
        $(document).ready(function() {
            // execute
            (function() {
                // map options
                var options = {
                    zoom: 5,
                    center: new google.maps.LatLng(39.909736, -98.522109), // centered US
                    mapTypeId: google.maps.MapTypeId.TERRAIN,
                    mapTypeControl: false
                };

                // init map
                var map = new google.maps.Map(document.getElementById('map_canvas'), options);

                // NY and CA sample Lat / Lng
                var southWest = new google.maps.LatLng(40.744656, -74.005966);
                var northEast = new google.maps.LatLng(34.052234, -118.243685);
                var lngSpan = northEast.lng() - southWest.lng();
                var latSpan = northEast.lat() - southWest.lat();

                // set multiple marker
                for (var i = 0; i < 250; i++) {
                    // init markers
                    var marker = new google.maps.Marker({
                        position: new google.maps.LatLng(southWest.lat() + latSpan * Math.random(), southWest.lng() + lngSpan * Math.random()),
                        map: map,
                        title: 'Click Me ' + i
                    });

                    // process multiple info windows
                    (function(marker, i) {
                        // add click event
                        google.maps.event.addListener(marker, 'click', function() {
                            infowindow = new google.maps.InfoWindow({
                                content: 'Hello, World!!'
                            });
                            infowindow.open(map, marker);
                        });
                    })(marker, i);
                }
            })();
        });
        </script>
    </head>
    <body>
        <div id="map_canvas" style="width: 800px; height:500px;"></div>
    </body>
</html>

Screenshot of 250 Markers:

Google Maps API V3.11 with Multiple Markers

It will automatically randomize the Lat/Lng to make it unique. This example will be very helpful if you want to test 500, 1000, xxx markers and performance.


This is the simplest I could reduce it to:

<!DOCTYPE html>
<html> 
<head> 
  <meta http-equiv="content-type" content="text/html; charset=UTF-8" /> 
  <title>Google Maps Multiple Markers</title> 
  <script src="http://maps.google.com/maps/api/js?key=YOUR_API_KEY" 
          type="text/javascript"></script>
</head> 
<body>
  <div id="map" style="width: 500px; height: 400px;"></div>

  <script type="text/javascript">
    var locations = [
      ['Bondi Beach', -33.890542, 151.274856, 4],
      ['Coogee Beach', -33.923036, 151.259052, 5],
      ['Cronulla Beach', -34.028249, 151.157507, 3],
      ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
      ['Maroubra Beach', -33.950198, 151.259302, 1]
    ];
    
    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 10,
      center: new google.maps.LatLng(-33.92, 151.25),
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
    
    var infowindow = new google.maps.InfoWindow();

    var marker, i;
    
    for (i = 0; i < locations.length; i++) {  
      marker = new google.maps.Marker({
        position: new google.maps.LatLng(locations[i][1], locations[i][2]),
        map: map
      });
      
      google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() {
          infowindow.setContent(locations[i][0]);
          infowindow.open(map, marker);
        }
      })(marker, i));
    }
  </script>
</body>
</html>

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SCREENSHOT

Google Maps Multiple Markers

There is some closure magic happening when passing the callback argument to the addListener method. This can be quite a tricky topic if you are not familiar with how closures work. I would suggest checking out the following Mozilla article for a brief introduction if it is the case:

❯ Mozilla Dev Center: Working with Closures