<!DOCTYPE html>
<html>
<body>
<h1>button popovertarget 属性</h1>
<h1 popover id="myheader">Hello</h1>
<button popovertarget="myheader">点击我！</button>
<p>单击该按钮，将在显示和隐藏弹出框元素之间切换。</p>
</body>
</html>