title: Bind more popups to the same marker or merge popups content
body: <p>I have a JSON in which there are places with their coordinates and their textual content to be inserted in the relative marker's popup.</p>
  <p>If in the JSON there is 2 times the same place (with the same coordinates), I have to bind 2 popups with their respective contents on the same marker (or at most I have to update the popup with the new content while keeping the old one).</p>
  <pre><code>&lt;html&gt;
  &lt;head&gt;
      &lt;!-- Libraries leaflet/jquery for may project--&gt;
     &lt;script src=&quot;https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js&quot;&gt;&lt;/script&gt;
     &lt;link rel=&quot;stylesheet&quot; href=&quot;https://unpkg.com/leaflet@1.3.1/dist/leaflet.css&quot; /&gt;
     &lt;script src=&quot;https://unpkg.com/leaflet@1.3.1/dist/leaflet.js&quot;&gt;&lt;/script&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
       &lt;div id=&quot;map&quot; style=&quot;width:100%; height: 100%&quot;&gt;&lt;/div&gt;
       
       &lt;script&gt;
       // my json data
       var data = [
          {
            &quot;name&quot; : &quot;Location A&quot;,
            &quot;lat&quot; :&quot;27&quot;,
            &quot;long&quot; : &quot;29&quot;,
            &quot;popupContent&quot; : &quot;content 1&quot;
          },
          {
            &quot;name&quot; : &quot;Location B&quot;,
            &quot;lat&quot; :&quot;51&quot;,
            &quot;long&quot; : &quot;12&quot;,
            &quot;popupContent&quot; : &quot;content 2&quot;
          },
          {
            &quot;name&quot; : &quot;Location A&quot;,
            &quot;lat&quot; :&quot;27&quot;,
            &quot;long&quot; : &quot;29&quot;,
            &quot;popupContent&quot; : &quot;content 3&quot;
          }
       ]
  
  
       //init leaflet  map
       var map = new L.Map('map');                       
              
       L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
          attribution: '&amp;copy; &lt;a href=&quot;http://openstreetmap.org&quot;&gt;OpenStreetMap&lt;/a&gt; contributors',
          maxZoom: 18
       }).addTo(map);
       var italy = new L.LatLng(42.504154,12.646361); 
       map.setView(italy, 6);
  
  
  
       //iterate my json data and create markers with popups
       for(let key in data){
         L.marker([data[key].lat,data[key].long]).bindPopup(data[key].popupContent).addTo(map)
       }
       &lt;/script&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  <p>With this code, the third place overrides the first, and I have a single marker and a single popup with written &quot;content 3&quot;.</p>
  <p>I would like 2 popups (one with written &quot;content 1&quot; and one with &quot;content 3&quot;) or one single popup with all two contents.</p>