js 事件委托

打印出 div#wrap 里的直接子元素 div

<div id="wrap">
  <div class="div1">
    <span>div1>span1</span>
    <span>div1>span2</span>
    <p>
      div1>p
      <span>div1>p>span</span>
    </p>
    <div>div1>div</div>
  </div>
  <p class="p1">
    <p>p>p1</p>
    <p>p>p2</p>
  </p>
  <div class="div2">div2</div>
</div>

let wrap = document.getElementById('wrap');
wrap.onclick = function (e) {
  let target = e.target;
  while (target !== wrap) {
    if (target.nodeName === 'DIV' && target.parentNode === wrap) {
      console.log(target);
      break;
    }
    target = target.parentNode
  }
}