<button id="btn" ondblclick="dblclickEvent()">ダブルクリック！</button>
*{
  text-align:center;
}

#btn{
  margin-top:20px;
}
const btn = document.getElementById('btn');

function dblclickEvent(){
  btn.insertAdjacentHTML('afterend', '<p>ダブルクリックされました</p>');
};

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.