代码示例:(标识:jsck_element_previouselementsibling)
<!DOCTYPE html>
<html>
<body>

<h1>Element 对象</h1>

<h2>previousElementSibling 属性</h2>

<ul>
  <li id="item1">Coffee(第一项)</li>
  <li id="item2">Tea(第二项)</li>
</ul>

<p>第二个列表项的上一个同胞项的文本是:</p>

<p id="demo"></p>

<script>
let text = document.getElementById("item2").previousElementSibling.innerHTML; 
document.getElementById("demo").innerHTML = text;
</script>

</body>
</html>
运行结果: