Chrome/Firefox mouseenter difference

Hover over the div and refresh the page.

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.js"></script>
<div id="my-div">
</div>

CSS

#my-div {
  width: 150px;
  height: 150px;
  background-color: #aaaaaa;
}

JavaScript

let div = document.getElementById('my-div');

div.addEventListener('mouseenter', function () {
  div.innerHTML = 'mouseenter';
});