点击按钮内的文字，谁是目标？

<div id="panel"><button id="go"><span id="icon">点击此文字</span></button></div>
<script>
  const panel = document.querySelector('#panel');
  const button = document.querySelector('#go');
  panel.addEventListener('click', () => console.log('父：捕获'), true);
  button.addEventListener('click', event => {
    console.log(event.target.id, event.currentTarget.id);
  });
  panel.addEventListener('click', () => console.log('父：冒泡'));
</script>

提问：只点击 span 文字时，按顺序写出三条输出。再点击按钮内部但 span 外的区域，哪两个 id 会变化？