登录模式和下拉菜单不起作用

Question

我创建了这段代码，但由于某种原因，登录模式和下拉菜单都不起作用。

jsfiddle.net

<nav class="navbar navbar-inverse navbar-fixed-top" role="navigation">
            <div class="container">
                <div class="navbar-header">
                    <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
                        <span class="sr-only">Toggle navigation</span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                        <span class="icon-bar"></span>
                    </button>

                </div>
                <div id="navbar" class="navbar-collapse collapse">
                    <ul class="nav navbar-nav">
                        <li class="active"><a href="index.html"><span class="glyphicon glyphicon-home"
                             aria-hidden="true"></span> Home</a></li>
                        <li><a href="aboutus.html"><span class="glyphicon glyphicon-info-sign"
                             aria-hidden="true"></span> About</a></li>
                        <li class="dropdown">
                            <a href="#" class="dropdown-toggle" data-toggle="dropdown"
                             role="button" aria-haspopup="true" aria-expanded="false"><span class="glyphicon glyphicon-list-alt" aria-hidden="true"></span>
                             Parks <span class="caret"></span></a>
                            <ul class="dropdown-menu">
                                <li><a href="#">Alcazar Park</a></li>
                                <li><a href="#">Municipality Park</a></li>
                                <li><a href="#">OSE Park</a></li>
                            </ul>
                        </li>
                        <li><a href="contactus.html"><span class="fa fa-envelope-o"
                             aria-hidden="true"></span> Contact</a></li>
                    </ul>
                     <ul class="nav navbar-nav navbar-right">
                        <li><a data-toggle="modal" data-target="#loginModal">
                        <span class="glyphicon glyphicon-log-in"></span> Login</a>
                        </li>
                    </ul>
                </div>
            </div>
        </nav>       
       <div id="loginModal" class="modal fade" role="dialog">
            <div class="modal-dialog">
            <!-- Modal Content -->
                <div class="modal-content">
                    <div class="modal-header">
                        <button type="button" class="close" data-dismiss="modal">&times;</button>
                        <h4 class="modal-title">Login </h4>
                    </div>
                    <div class="modal-body">
                        <form class="form-inline">
                            <div class="form-group">
                                <label class="sr-only" for="email">Email address</label>
                                <input type="email" id="email" name="email" placeholder="Email" class="form-control input-sm">
                            </div>
                             <div class="form-group">
                                 <label class="sr-only" for="password">Password</label>
                                <input type="password" id="password" name="password" placeholder="Password" class="form-control input-sm">
                            </div>    
                                 <div class="checkbox">
                                    <label style="color:black;">
                                        <input type="checkbox"><small>Remember Me</small>
                                    </label>
                                </div>  
                                <button type="submit" id="signIn" class="btn btn-info btn-sm">Sign In</button>
                                <button type="button" id="cancelModal" class="btn btn-default btn-sm" data-dismiss="modal">Cancel</button>
                        </form>             
                    </div>
                </div>
            </div>
        </div>

任何想法可能出了什么问题？我觉得这很奇怪，因为我找不到任何错误。

谢谢

西欧。

Answer 1

它缺少jquery库。

https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js

https://jsfiddle.net/nwen88pk/3/

Answer 2

对于您正在寻找的两个 Bootstrap 功能(Modal 和 Dropdown(，jQuery 是必需的。你的小提琴中的代码缺少jQuery库。

https://code.jquery.com/jquery-3.2.1.min.js

此外，在包含 Bootstrap JavaScript 之前，您必须包含 jQuery 库。