anchor.diff:    <body>
       <% if @visualization.public? %>
         <div id="map"></div>
  +      <div id="not_supported_dialog" style="display: none">
  +          <h1>CartoDB</h1>
  +          <p>This visualization only works in modern brosers. Updagre yours and enjoy</p>
  +      </div>
         <div class="cartodb-text">Create your own custom maps with <a href="http://cartodb.com" target="_blank">CartoDB</a></div>
       <% end %>
   
  
positive.code:         cartodb.createVis('map', '<%= v2_vizjson_url(@visualization) %>', opt, function(vis) {
            // add here your code
            window.vis = vis;
          });
        });
  
      </script>
  
negative.code:         return params;
        }
  
        function manageError(err, layer) {
            if(layer && layer.get('type') === 'torque') {
                $('#not_supported_dialog').show();
            }
        }
  
        $(document).ready(function(){
  
          var bool_fn = function(v) { return v == 'true' }
  