javascript - 显示下拉菜单中选择的内容: bootstrap

我有以下HTML，

<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap Example</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
</head>
<body>

<div class="container">
  <div class="dropdown">
    <button type="button" class="btn btn-warning dropdown-toggle" data-toggle="dropdown">
      Dropdown button
    </button>
    <div id="custom" class="dropdown-menu">
      <a class="dropdown-item" href="#">Normal</a>
      <a class="dropdown-item" href="#">Active</a>
      <a class="dropdown-item" href="#">Disabled</a>
    </div>
  </div>
</div>

<script>
document.getElementById('custom').addEventListener("click", myFunction);

function myFunction() {
  alert(this.textContent);
}
</script>

</body>
</html>

我正在尝试alert并将button文本设置为drop-down中选择的文本。

我可以通过将id设置为dropdown-item并在JS中读取它来获取值。但是我有n个dropdown-item，所以添加id是不可行的。

jQuery中有可用的解决方案，但是如何不使用jQuery来做到这一点。？

最佳答案

您可以访问目标元素的innerHTML或innerText属性：

document.getElementById('custom').addEventListener("click", myFunction);

function myFunction(e) {
  alert(e.target.innerText);
}

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>

<div class="container">
  <div class="dropdown">
    <button type="button" class="btn btn-warning dropdown-toggle" data-toggle="dropdown">
      Dropdown button
    </button>
    <div id="custom" class="dropdown-menu">
      <a class="dropdown-item" href="#">Normal</a>
      <a class="dropdown-item" href="#">Active</a>
      <a class="dropdown-item" href="#">Disabled</a>
    </div>
  </div>
</div>

关于javascript - 显示下拉菜单中选择的内容: bootstrap ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/57054715/