anchor.diff:  <link href="https://unpkg.com/leaflet.markercluster@1.3.0/dist/MarkerCluster.Default.css" rel="stylesheet" />
   
   <script type="text/javascript">
  +  var catalog = document.getElementById('catalog_slug').value;
     var map = L.map('map-<%= container.item_type %>');
  +  var locale = '<%= I18n.locale %>';
     L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
       attribution: 'Map data &copy; <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors, <a href="https://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>',
       maxZoom: 18
  
positive.code: <textarea id="geojson-<%= container.item_type %>" style="display: none;"><%= container.geojson %></textarea>
  <textarea id="bounds" style="display: none;"><%= container.default_bounds.to_json.html_safe %></textarea>
  <div id="map-<%= container.item_type %>" style="width: 100%; height: 400px;"></div>
  
  <script src="https://unpkg.com/leaflet.markercluster@1.3.0/dist/leaflet.markercluster.js"></script>
  
negative.code:     fid = marker.feature.properties.id;
  
      var request = new XMLHttpRequest();
      request.open('GET', '/api/v1/catalogs/'+catalog+'/items/'+fid+'.json');
  
      request.onload = function() {
        if (request.status >= 200 && request.status < 400) {
          // Success!
          var feat = JSON.parse(request.responseText);
          marker._popup.setContent('<a href="'+feat._links.html+'">'+_t.view_item[locale]+'</a>');
        } else {
          marker._popup.setContent(_t.error[locale]);
        }
      };
  
      request.onerror = function() {
        marker._popup.setContent(_t.error[locale]);
      };
  
      request.send();
    }
  
    var _t = {
      "loading": {
        fr: "Chargement...",
        en: "Loading...",
        de: "Laden...",
        it: "Carico..."
      },
      "view_item": {
        fr: "Consulter la fiche",
        en: "View item",
        de: "Element anschauen",
        it: "Consultare l'oggetto"
      },
      "error": {
        fr: "Erreur. Impossible de charger l'objet.",
        en: "Error. Unable to load item data.",
        de: "Fehler. Kann Element nicht laden.",
        it: "Errore. Impossibile caricare l'oggetto."
      }
    }
  
  </script>
  