Leaflet layer selector with CartoDB layers

<!DOCTYPE html>
<html>
  <head>
    <title>Leaflet layer selector with CartoDB layers</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <link rel="shortcut icon" href="https://cartodb.com/assets/favicon.ico" />
    <style> html, body, #map { height:100%; padding:0; margin:0 } </style>
    <link rel="stylesheet" href="https://libs.cartocdn.com/cartodb.js/v3/themes/css/cartodb.css" />
  </head>
  <body>
    <div id="map"></div>
    
    
    <script src="https://libs.cartocdn.com/cartodb.js/v3/cartodb.js"></script>

// create leaflet map
        var map = L.map('map', { 
          zoomControl: false,
          center: [43, 0],
          zoom: 3
        })

// add a base layer
        L.tileLayer('https://tile.stamen.com/toner/{z}/{x}/{y}.png', {
          attribution: 'Stamen'
        }).addTo(map);

// add cartodb layer with one sublayer
        cartodb.createLayer(map, {
          user_name: 'examples',
          type: 'cartodb',
          sublayers: [{
             sql: 'select * from country_boundaries',
             cartocss: '#layer { polygon-fill: #F00; polygon-opacity: 0.3; line-color: #F00; }',
             interactivity: 'cartodb_id'
          }]
        }).addTo(map);

cartodb.createLayer(map, {
          user_name: 'xavijam',
          type: 'cartodb',
          sublayers: [{
            sql: 'select * from map',
            cartocss: '#layer { polygon-fill: green; polygon-opacity: 0.3; line-color: #F00; }',
            interactivity: 'cartodb_id'
          }]
        })
        .on('done', function(lyr) {
          L.control.layers(null, { 'maps': lyr }).addTo(map);
        })
        
      }
 
      window.onload = main;
    </script>
  </body>
</html>

Modified http://libs.cartocdn.com/cartodb.js/v3/cartodb.js to a secure url

https://libs.cartocdn.com/cartodb.js/v3/cartodb.js