当我们只有孩子的ID时，如何使用js更改父div的宽度和高度

Question

How can I change the width and height of parent div using js when we only have the id of the child

<li>
  <span id="head-ing"><?=$row['subject']?></span>
  <script>
    /*what js to use*/
  </script>
</li>

The div comes from the Database. so i cannot modify that

Answer 1

使用parentElement ：

document.getElementById("myLI").parentElement.style.width = "200px";

Answer 2

var child = document.getElementById("childId");
parent = child.parentNode;
parent.style.width= "100px";
parent.style.height= "100px";