index.html

## index.html
<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
    <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
    <style>html, body, #map { height: 100%; padding: 0; margin: 0 }</style>
  </head>
  <body>
    <div id="map"></div>
  <!-- include cartodb css  -->
    <link rel="stylesheet" href="https://cartodb-libs.global.ssl.fastly.net/cartodb.js/v3/3.15/themes/css/cartodb.css" />
    <!-- include cartodb.js library -->
     <script src="https://cartodb-libs.global.ssl.fastly.net/cartodb.js/v3/3.15/cartodb.js"></script>


    <script type="text/javascript">
      var layer;

      function main() {

        var map = L.map('map', {
          zoomControl: false,
          center: [20, 20],
          zoom: 2
        });

        // add basemap
       L.tileLayer('http://{s}.basemaps.cartocdn.com/light_nolabels/{z}/{x}/{y}.png', {attribution: '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors, &copy; <a href="http://cartodb.com/attributions">CartoDB</a>'}).addTo(map);

        cartodb.createLayer(map, {
          user_name: 'documentation',
          type: 'cartodb',
          sublayers: [{
            sql: "select european.the_geom, european.the_geom_webmercator, european.cartodb_id, european.admin ,world_table.area FROM european, world_table  WHERE european.adm0_a3 = world_table.iso3",
            cartocss: "#world_table{ line-color: #FFF; line-opacity: 1; line-width: 1; polygon-opacity: 0.8;} #world_table[area <= 1638094.0] { polygon-fill: #B10026; } #world_table [ area <= 34895.0] { polygon-fill: #E31A1C; } #world_table [ area <= 24193.0] { polygon-fill: #FC4E2A; } #world_table [ area <= 10025.0] { polygon-fill: #FD8D3C; } #world_table [ area <= 6889.0] { polygon-fill: #FEB24C; } #world_table [ area <= 4808.0] { polygon-fill: #FED976; } #world_table [ area <= 3288.0] { polygon-fill: #FFFFB2; }",
            interactivity: "cartodb_id"
          }]
        }, {https: true})
          .addTo(map)
          .on('done', function(lyr) {

            cartodb.vis.Vis.addInfowindow(map, lyr.getSubLayer(0), ['area','admin'])

          }).on('error', function() {
            console.log("some error occurred");
          });
      }

      window.onload = main;

    </script>
  </body>
</html>