Edit in JSFiddle

var clipboard = new Clipboard('.btn');
clipboard.on('success', function(e) {
  console.info('Trigger:', e.trigger);
});
clipboard.on('error', function(e) {
  console.error('Trigger:', e.trigger);
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/1.5.8/clipboard.min.js"></script>

<p>
  <button class="btn" data-clipboard-text="ABC">ABCをコピー</button>
</p>

<p>
  <input id="data" type="text" size="20">
  <button class="btn" data-clipboard-target="#data">入力をコピー</button>
</p>

<p>
  <input id="data2" type="text" size="20">
  <button class="btn" data-clipboard-target="#data2" data-clipboard-action="cut">入力をカット</button>
</p>