JavaScript星露谷主题待办列表：叉号与勾选标记不显示问题

完整可运行代码 #

HTML #

<div id="myDIV" class="header">
  <h2>My To Do List</h2>
  <input type="text" id="myInput" placeholder="Title...">
  <span onclick="newElement()" class="addBtn">Add</span>
</div>

<ul id="myUL">
  <li>Water Crops</li>
  <li> Check coop</li>
  <li>give gift to sweetie</li>
  <li>visit mines</li>
</ul>

CSS #

* {
  box-sizing: border-box;
}

body {
  background: url(stardew_background.png);
}

ul {
  margin: 0;
  padding: 0;
}

ul li {
  cursor: pointer;
  position: relative;
  padding: 12px 8px 12px 40px;
  background: #eee;
  font-size: 18px;
  transition: 0.2s;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

ul li:nth-child(odd) {
  background: #f9f9f9;
}

ul li:hover {
  background: #ddd;
}

ul li.checked {
  background: #888;
  color: #fff;
  text-decoration: line-through;
}

ul li.checked::before {
  content: '';
  position: absolute;
  border-color: #fff;
  border-style: solid;
  border-width: 0 2px 2px 0;
  top: 10px;
  left: 16px;
  transform: rotate(45deg);
  height: 15px;
  width: 7px;
}

.close {
  position: absolute;
  right: 0;
  top: 0;
  padding: 12px 16px 12px 16px;
  color: #555; /* 添加默认叉号颜色 */
}

.close:hover {
  background-color: #f44336;
  color: white;
}

.header {
  background-color: #f44336;
  padding: 30px 40px;
  color: white;
  text-align: center;
}

.header:after {
  content: "";
  display: table;
  clear: both;
}

input {
  margin: 0;
  border: none;
  border-radius: 0;
  width: 75%;
  padding: 10px;
  float: left;
  font-size: 16px;
}

.addBtn {
  padding: 10px;
  width: 25%;
  background: #d9d9d9;
  color: #555;
  float: left;
  text-align: center;
  font-size: 16px;
  cursor: pointer;
  transition: 0.3s;
  border-radius: 0;
}

.addBtn:hover {
  background-color: #bbb;
}

JavaScript #

document.addEventListener('DOMContentLoaded', function() {
  // 初始化现有列表项的叉号
  const myNodelist = document.getElementsByTagName("LI");
  for (let i = 0; i < myNodelist.length; i++) {
    const span = document.createElement("SPAN");
    const txt = document.createTextNode("\u00D7");
    span.className = "close";
    span.appendChild(txt);
    myNodelist[i].appendChild(span);
  }

  // 绑定叉号点击删除事件
  const closeButtons = document.getElementsByClassName("close");
  for (let i = 0; i < closeButtons.length; i++) {
    closeButtons[i].onclick = function() {
      this.parentElement.style.display = "none";
    }
  }

  // 绑定列表项点击勾选事件
  const list = document.querySelector('ul');
  list.addEventListener('click', function(ev) {
    if (ev.target.tagName === 'LI') {
      ev.target.classList.toggle('checked');
    }
  }, false);

  // 新增任务函数
  window.newElement = function() {
    const li = document.createElement("li");
    const inputValue = document.getElementById("myInput").value;
    li.appendChild(document.createTextNode(inputValue));
    
    if (!inputValue) {
      alert("You must write something!");
      return;
    }
    
    document.getElementById("myUL").appendChild(li);
    document.getElementById("myInput").value = "";

    // 给新任务添加叉号和事件
    const span = document.createElement("SPAN");
    const txt = document.createTextNode("\u00D7");
    span.className = "close";
    span.appendChild(txt);
    li.appendChild(span);
    
    span.onclick = function() {
      this.parentElement.style.display = "none";
    }
  }
});

内容的提问来源于stack exchange，提问作者IcedLatte