我正在使用 Bootstrap 和 Codeigniter ，我的问题是关于下拉菜单。 在首页中，它非常合适，但是在我使用控制器调用页面后，它就不再起作用了（有时我需要它来从数据库中获取一些数据）
When it's working When it's doesn't work 这是HTML的下拉列表
<li class='nav-item dropdown'>
<a class='nav-link dropdown-toggle' href="" role='button' id="dropdownCadastro"
data-toggle='dropdown' aria-haspopup="true" aria-expanded="false">
Projeto
</a>
<div class="dropdown-menu shadow border-0" aria-labelledby="dropdownCadastro">
<a class="dropdown-item js-scroll-trigger" href='<?php echo base_url('projeto');?> '>Cadastrar Projeto</a>
<a class="dropdown-item js-scroll-trigger" href='<?php echo base_url('avaliacao');?> '>Avaliar Projeto</a>
<a class="dropdown-item js-scroll-trigger" href='<?php echo base_url('consultarProjetoServidor');?> '>Consultar Projeto</a>
</div>
</li>
标题
<link rel="stylesheet" href="<?php echo base_url('assets/vendor/bootstrap/css/bootstrap.min.css') ?>" >
<link rel="stylesheet" href="<?php echo base_url('fonts/fontawesome-free/css/all.min.css') ?>" >
<!-- Custom fonts for this template -->
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Catamaran:100,200,300,400,500,600,700,800,900">
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato:100,100i,300,300i,400,400i,700,700i,900,900i">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.0/css/all.css"
integrity="sha384-lZN37f5QGtY3VHgisS14W3ExzMWZxybE1SJSEsQp9S+oqd12jhcu+A56Ebc1zFSJ" crossorigin="anonymous">
<!-- Custom styles for this template -->
<link rel="stylesheet" href="<?php echo base_url('assets/css/one-page-wonder.min.css') ?>" >
页脚
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>