打开对话框时，列表视图按位置设置单个项目的颜色

<ul id="listView">
  <li>项目1</li>
  <li>项目2</li>
  <li>项目3</li>
  <li>项目4</li>
</ul>

#listView li {
  padding: 10px;
  border-bottom: 1px solid #ccc;
}

#listView li:nth-child(1) {
  background-color: red;
}

#listView li:nth-child(2) {
  background-color: blue;
}

#listView li:nth-child(3) {
  background-color: green;
}

#listView li:nth-child(4) {
  background-color: yellow;
}

var listView = document.getElementById("listView");
var items = listView.getElementsByTagName("li");

for (var i = 0; i < items.length; i++) {
  items[i].addEventListener("click", function() {
    this.style.backgroundColor = "orange";
  });
}