paste-test.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  <h2>Paste here to see contents of clipboard:</h2>
  <div style="width: 200px; height: 200px; border: 1px solid black; overflow: auto;" contenteditable="true" id="test"></div>

  <br>
  <h2>Content Analysis:</h2>
  <textarea id="content-report" cols="100" rows="20"></textarea>

  <script>
    document.getElementById('test').addEventListener('paste', function(e) {
      var items = e.clipboardData.items;
      var contents = '';

      for (var i = 0; i < items.length; i++) {
        console.log(items[i].type, e.clipboardData.getData(items[i].type));

        contents += 'Type:\n' + items[i].type + '\n\n';
        contents += 'Content:\n' + e.clipboardData.getData(items[i].type) + '\n---------------------------------\n\n';
        document.getElementById('content-report').innerHTML = contents;
      }

      
    })
  </script>
</body>
</html>