W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {
  box-sizing: border-box;
}

ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
}

ul li {
  border: 1px solid #ddd;
  margin-top: -1px; /* 防止双边框 */
  background-color: #f6f6f6;
  padding: 12px;
  text-decoration: none;
  font-size: 18px;
  color: black;
  display: block;
  position: relative;
}

ul li:hover {
  background-color: #eee;
}

.close {
  cursor: pointer;
  position: absolute;
  top: 50%;
  right: 0%;
  padding: 12px 16px;
  transform: translate(0%, -50%);
}

.close:hover {background: #bbb;}
</style>
</head>
<body>

<h1>可关闭的列表项</h1>

<p>点击列表项右侧的“×”符号可关闭/隐藏它。</p>

<ul>
  <li>Adele</li>
  <li>Agnes<span class="close">×</span></li>

<li>Billy<span class="close">×</span></li>
  <li>Bob<span class="close">×</span></li>

<li>Calvin<span class="close">×</span></li>
  <li>Christina<span class="close">×</span></li>
  <li>Cindy</li>
</ul>

for (i = 0; i < closebtns.length; i++) {
  closebtns[i].addEventListener("click", function() {
    this.parentElement.style.display = 'none';
  });
}
</script>

</body>
</html>