Clone contenteditable div without text

How can I clone a new row without also copying the text that has been inserted inside the contenteditable div? I want a new blank div to type into. Many thanks

<div id="wrapper">
  <div id="row">
    <p><strong>Heading</strong></p>
    <div contenteditable="true" data-placeholder="Type here..."></div>
  </div>
</div>
<button id="button" onlick="duplicate()">Add another row</button>

document.getElementById('button').onclick = duplicate;

var i = 0;
var original = document.getElementById('row');

function duplicate() {
    var clone = original.cloneNode(true);
    clone.id = "row" + ++i;
    original.parentNode.appendChild(clone);
}