我的导航栏下拉菜单按钮不工作？
我正在尝试使用下面代码中所示的导航栏按钮，我已经附上了index.html和style.css文件的代码。我已经附上了index.html和style.css文件的代码。谁能帮我解决这个问题？下拉菜单不显示
.navbar-brand h1 {
margin: 0;
font-size: 25px;
float: left;
}<!DOCTYPE HTML>
<HTML>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, intial-scale=1">
<link rel="stylesheet" type="text/css" href="css/styles.css">
<link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
<link href="https://fonts.googleapis.com/css2?family=Raleway&display=swap" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="css/styles.css">
<script src="js/jquery-3.5.0.min"></script>
<script src="js/bootstrap.min.js"></script>
<script src="js/script.js"></script>
<title>Module 3 Solution</title>
</head>
<body>
<header>
<nav id="header-nav" class="navbar navbar-default">
<div class="container">
<div class="navbar-header ">
<a href="index.html" class="float-sm-left visible-md visible-lg">
<div id="logo-img" alt="logo"></div>
</a>
<div class="navbar-brand" class="float-left">
<a href="index.html">
<h1>Food, LLC</h1>
</a>
</div>
</div>
<div class="navbar-header">
<span class="navbar-toggler-icon"></span>
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
<span class="sr-only">Toggle Navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<div class="collapse navbar-collapse" id="myNavbar">
<ul class="nav navbar-nav visible-xs">
<li><a href="#chicken">Chicken</a></li>
<li><a href="#beef">Beef</a></li>
<li><a href="#sushi">Susuhi</a></li>
</ul>
</div>
</div>
</div>
</nav>
</header>
</body>
</HTML>EDIT: 试着把你的JQuery和Bootstrap JS文件移到右边的上方。</body> 标签（将Bootstrap CSS留在 <head>).
我已经做了一个 鳕鱼笔 给你。这是Bootstrap文档中的基本代码。我把你的一些自定义代码换了进去（并删除了重复的代码），用最小的代码就能在那里工作了，如果还是不能为你工作，那就是其他地方的代码需要修改。
<head>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
</head>
<body>
<nav class="navbar navbar-light bg-light">
<a class="float-sm-left" href="index.html">
<h1>Food, LLC</h1>
</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#myNavbar" aria-controls="myNavbar" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="myNavbar">
<ul class="navbar-nav mr-auto mt-2 mt-lg-0 visible-xs">
<li class="nav-item"><a href="#chicken">Chicken</a></li>
<li class="nav-item"><a href="#beef">Beef</a></li>
<li class="nav-item"><a href="#sushi">Susuhi</a></li>
</ul>
</div>
</nav>
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
</body>