div出现后如何获得div？

Question

我如何获取add__deal__btn并对其进行处理？页面加载时，它不存在，我也无法获取，但是添加后如何获取？

let addTitle = document.querySelector('.add__title');
let addBtn = document.querySelector('.add__btn');
let tasks = document.querySelector('.tasks');
let addDealBtn = [];

addBtn.onclick = function() {
  let task = document.createElement('div');
  task.className = 'task__card';
  let taskTitle = document.createElement("h4");
  taskTitle.innerHTML = addTitle.value
  task.appendChild(taskTitle)
  addDealBtn = document.createElement("button");
  addDealBtn.className = "add__deal__btn";
  addDealBtn.innerHTML = "Add deal";
  task.appendChild(addDealBtn);
  tasks.append(task);
}

<div class="add">
  <input type="text" class="add__title">
  <br>
  <button class="add__btn">Add</button>
</div>

<div class="tasks"></div>

谢谢

Answer 1

单击.add__btn后：

let addBtn = document.querySelector('.add__btn');
addBtn.click(); // <= A computational click standing in for a user click

您可以使用以下方法获取add__deal__btn：

document.getElementsByClassName('add__deal__btn')[0];

Answer 2

document.getElementsByClassName("add__btn")[0]