【发布时间】：2019-07-03 00:57:07
【问题描述】：
我正在使用引导下拉功能创建导航栏。https://getbootstrap.com/docs/4.0/components/dropdowns/ 导航栏中的每个按钮在下拉菜单中显示相同的信息。示例：练习按钮显示分配，分配按钮也显示分配。
<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS" crossorigin="anonymous">
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js" integrity="sha384-wHAiFfRlMFy6i5SRaxvfOCifBUQy1xHdJ/yoi7FRNXMRBu5WHdZYu1hA6ZOblgut" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/js/bootstrap.min.js" integrity="sha384-B0UglyR+jN6CkvvICOB2joaf5I4l3gm9GU6Hc1og6Ls7i6U/mkkaduKaBhlAXv9k" crossorigin="anonymous"></script>
<title>Hello, world!</title>
</head>
<body>
<h1>Hello, world!</h1>
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Assignments
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
<a class="dropdown-item" href="http://ec2-3-17-178-150.us-east-2.compute.amazonaws.com/home/home.php">Assignment 1: PHP Page</a>
<a class="dropdown-item" href="#">Assignment 2: My SQL Form <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">Assignment 3: JavaScript Validation/code <i>(Coming Soon)</i></a>
</div>
<!--Exercise dropdown info-->
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Exercises
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
<a class="dropdown-item" href="http://ec2-3-17-178-150.us-east-2.compute.amazonaws.com/HelloWorld.php">CE01: Hello World<i>Coming Soon</i></a>
<a class="dropdown-item" href="#">CE02: Days of the Week <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE03: Using Forms and $_POST <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE04: Story Idea Generator <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE05: Workbench Setup <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE06: Adding and removing from Database <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE07: Forum Database <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE08: Monster Manager <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE09: Adding and removing from Database <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE010: JavaScript Objects <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE011: JS Control <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE012: Session Control <i>(Coming Soon)</i></a>
<a class="dropdown-item" href="#">CE013: Login<i>(Coming Soon) </i></a>
<a class="dropdown-item" href="#">CE014: Shopping Cart <i>(Coming Soon)</i></a>
</div>
</body>
</html>【问题讨论】：
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ID 必须是唯一的
标签： html css bootstrap-4