这是一个简单的引导导航栏，带有一些li链接。我想将下拉列表转换为下拉列表。
.navbar {
background-color: #34A8F0;
}
.nav-link{
display: flex;
flex-direction: column;
align-items: center;
}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<script src="https://use.fontawesome.com/f1e10fbba5.js"></script>
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
<!-- jQuery library -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<!-- Popper JS -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<!-- Latest compiled JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="style.css">
<title>Document</title>
</head>
<body>
<nav class="navbar navbar-expand-md navbar-light ">
<a class="navbar-brand" href="#">
Navbar
</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mx-auto">
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">User Managemnt</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item active">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Email</p>
</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Jobs</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">HRMS</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Sell</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item ">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Notification</p>
</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Expenses</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Report</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
<ul class="navbar-nav">
<li class="nav-item active">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Email</p>
</a>
</li>
</ul>
</div>
</nav>
</nav>
</body>
</html><div class="dropup">
<button class=" btn nav-value dropdown-toggle" type="button" data-toggle="dropdown">Sell
<span class="caret"></span></button>
<ul class="dropdown-menu">
<li><a href="#">All Sales</a></li>
<li><a href="#">Add Sales</a></li>
<li><a href="#">List POS</a></li>
<li><a href="#">POS</a></li>
<li><a href="#">List Drafts</a></li>
<li><a href="#">List Qoutation</a></li>
<li><a href="#">List Sell Return</a></li>
<li><a href="#">Shipment</a></li>
<li><a href="#">Discounts</a></li>
</ul>
</div>
.dropdown-menu.show{
top:-50px;
position:absolute;
}
试试这个
打开时在下拉列表中添加position:absolute和top:-75px。
.navbar {
background-color: #34A8F0;
}
.nav-link{
display: flex;
flex-direction: column;
align-items: center;
}
.dropdown-menu.show {
top: -75px;
position: absolute !important;
}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<script src="https://use.fontawesome.com/f1e10fbba5.js"></script>
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
<!-- jQuery library -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<!-- Popper JS -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<!-- Latest compiled JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="style.css">
<title>Document</title>
</head>
<body>
<nav class="navbar navbar-expand-md navbar-light ">
<a class="navbar-brand" href="#">
Navbar
</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mx-auto">
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">User Managemnt</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item active">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Email</p>
</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Jobs</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">HRMS</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Sell</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item ">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Notification</p>
</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Expenses</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Report</p>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
<ul class="navbar-nav">
<li class="nav-item active">
<a class="nav-link" href="#">
<p class="m-0 p-0"><i class="fa fa-home"></i></p>
<p class="m-0 p-0">Email</p>
</a>
</li>
</ul>
</div>
</nav>
</nav>
</body>
</html>