title: How to add a list of clicked items to an input field and be able to retrieve them?
body: <p>At the moment I am clicking on country regions and I adding their propriety name to an input field, i am doing this as I need to send the input value to backend. This is I could be clicking many countries, so this is what I currently do for one single country:</p>
  
  <pre><code>&lt;input type="text" id="usp-custom-3"&gt;
  
  function zoomToFeature(e) {
          this.getElement().classList.toggle('active');
          var name = e.target.feature.properties.name;
          jQuery("#usp-custom-3").val(name);
    }
  
    function onEachFeature(feature, layer) {
      layer.on({
        click: zoomToFeature
      });
    }
  </code></pre>
  
  <p>With <code>this.getElement().classList.toggle('active');</code> I mean when I click on a country polygon. As i said I might be clicking more than one country, so how to add more than one country name in the <code>input</code> like "Italy France Spain" and be able to remove them if we click again on it?</p>