Node: removeChild() メソッド

removeChild(child)

<div id="top">
  <div id="nested"></div>
</div>

let d = document.getElementById("top");
let d_nested = document.getElementById("nested");
let throwawayNode = d.removeChild(d_nested);

let node = document.getElementById("nested");
if (node.parentNode) {
  node.parentNode.removeChild(node);
}

let element = document.getElementById("idOfParent");
while (element.firstChild) {
  element.removeChild(element.firstChild);
}

<!--HTML コードの例-->
<div id="top"></div>

let top = document.getElementById("top");
let nested = document.getElementById("nested");
// TypeError が発生
let garbage = top.removeChild(nested);

<!--HTML コードの例-->
<div id="top">
  <div id="nested"></div>
</div>

let top = document.getElementById("top");
let nested = document.getElementById("nested");
// 最初の呼び出しでは正しくノードを取り除く
let garbage = top.removeChild(nested);
// NotFoundError が発生
garbage = top.removeChild(nested);