<!DOCTYPE html>
<html>
<head>
<style>
summary { display: none; }
span { background-color: red; }
</style>
</head>
<body onload="test()">
<div>
<div>
<details open>
<div>Hello1</div>
<span>Hello2</span>
<span>Hello3</span>
<summary></summary>
</details>
</div>
</div>
</body>
</html>