如何折叠移动设备的导航栏？

Question

 .navbar { background:white; border: 1px solid #008080; border-width: 1px 0; box-shadow: 0px -4px 3px rgba(50, 50, 50, 0.75), 0 8px 6px -6px black; } .navbar-contact, .nav { background: #008080; overflow: hidden; } .navbar-contact { max-height: 29px; } .bottom { margin-top: -30px; } /* White Angles (Common) */ .nav:before, .navbar-contact:after { content: ""; background: #fff; position: absolute; width: 2em; height: 4em; transform: rotate(30deg); } /* .navbar-contact angle position */ .navbar-contact:after { right: -1em; top: -0.5em; } /* .nav angle position */ .nav:before { left: -1em; top: -1em; } .head-text{ padding-top:1px; font-family:Righteous; text-align:center; color:#78ece9; } 

 <html> <head> <title>Contact</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"> <link href="http://computervision.in/bootstrap/css/bootstrap.min.css" rel="stylesheet"> <link href="http://computervision.in/css/style.css" rel="stylesheet"> </head> <!------ Include the above in your HEAD tag ----------> <body id="top"> <nav class="navbar p-0 fixed-top"> <div class="top d-flex w-100"> <div class="px-2 navbar-contact text-white position-relative flex-grow-1">Contact: <a class="text-white" href="#">+91 xxxxxxxxxx or + 91 xxxxxxxxxx </a></div> <div class="pt-1 pr-3 d-flex mt-auto bg-white position-relative"> <div class="dropdown"> <img class="position-relative" src="http://computervision.in/images/IN.png" height="50"> <div class="dropdown-content2"> <a class="my-font" href="courses.php">Courses</a> <a class="my-font" href="login.php">Student Login</a> <a class="my-font" href="#">Make Payments</a> <a class="my-font" href="#">Student Review</a> <a class="my-font" href="#">Verify Certificates</a> <a class="my-font" href="#">Online Registration</a> </div> </div> <div class="dropdown"> <img class="position-relative ml-3 mr-2" src="http://computervision.in/images/PV.png" height="55"> <div class="dropdown-content"> <a class="my-font" href="#">Gallery</a> <a class="my-font" href="#">Hot Jobs</a> <a class="my-font" href="#">Placement Cell</a> <a class="my-font" href="#">Top Placements</a> <a class="my-font" href="#">Placement Drive</a> <a class="my-font" href="placement.php">Placement Testimonials</a> </div> </div> </div> </div> <div class="bottom d-flex w-100"> <div class="navbar-brand"> <a class="navbar-brand mr-0" href="#"> <img src="http://computervision.in/images/logo.png" height="60"> </a> <button class="navbar-toggler" id="nav1" type="button" data-toggle="collapse" data-target="#navMain" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> </div> <ul class="nav mt-auto flex-grow-1 pl-4 position-relative" role="navigation" id="navMain"> <li class="nav-item active"><a class="nav-link my-font" href="index.php">Home</a></li> <li class="nav-item"><a class="nav-link my-font" href="about.php">About</a></li> <li class="nav-item "><a class="nav-link my-font" href="why.php">Why Computer Vision</a></li> <li class="nav-item"><a class="nav-link my-font" href="courses.php">Courses</a></li> <li class="nav-item"><a class="nav-link my-font" href="services.php">Services</a></li> <li class="nav-item"><a class="nav-link my-font" href="events.php">Events</a></li> <li class="nav-item"><a class="nav-link my-font" href="blogs.php">Blogs</a></li> <li class="nav-item"><a class="nav-link my-font blink" href="contact.php">Contact</a></li> <li class="nav-item"><a class="nav-link my-font" href="register.php">Register</a></li> </ul> </div> </nav> <!-- Contact Us Section --> </body> </html> 

我已经尝试了很多代码来使这个代码在移动设备中响应，因此当用户从移动设备访问我的页面时，他会得到一个折叠的导航栏。 我已经尝试了各种方式， navbar collapse类似乎甚至没有工作。 所以我删除了折叠导航栏的整个代码。 请帮帮我，我已经被困在这里好几天了。 不管怎么说，多谢拉。

Answer 1

这是折叠导航栏的小例子。 请试一试。 在帖子和全屏幕中运行代码段以查看其工作原理。

 <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous"> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script> <nav class="navbar navbar-expand-lg navbar-light bg-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 mr-auto"> <li class="nav-item active"> <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a> </li> <li class="nav-item"> <a class="nav-link" href="#">Link</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"> Dropdown </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 disabled" href="#">Disabled</a> </li> </ul> <form class="form-inline my-2 my-lg-0"> <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search"> <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button> </form> </div> </nav> 

Answer 2

 .navbar { border: 1px solid #008080; border-width: 1px 0; box-shadow: 0px -4px 3px rgba(50, 50, 50, 0.75), 0 8px 6px -6px black; } .navbar-contact, .nav, .navbar-nav { background: #008080; overflow: hidden; } .navbar-contact { max-height: 29px; } .bottom { margin-top: -30px; } /* White Angles (Common) */ .nav:before, .navbar-contact:after { content: ""; background: #fff; position: absolute; width: 2em; height: 2.5em; transform: skew(-30deg); } /* .navbar-contact angle position */ .navbar-contact:after { right: -1em; top: 0; } /* .nav angle position */ .nav:before { left: -1em; top: 0; } .navbar.navbar-expand-lg { flex-wrap: wrap; } .navbar-toggler { color: rgba(0,0,0,.5); border-color: rgba(0,0,0,.1); } .navbar .bottom.d-flex { flex-wrap: wrap; } .navbar-toggler-icon { border:1px solid #ddd; background-image: url("data:image/svg+xml,<svg viewBox='0 0 30 30' xmlns='http://www.w3.org/2000/svg'><path stroke='rgba(0, 0, 0, 0.5)' stroke-width='2' stroke-linecap='round' stroke-miterlimit='10' d='M4 7h22M4 15h22M4 23h22'/></svg>"); } 

 <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <nav class="navbar navbar-expand-lg p-0"> <div class="top d-flex w-100"> <div class="px-2 navbar-contact text-white position-relative flex-grow-1">Contact: <a class="text-white" href="#">+91 xxxxxxxxxx or xxxxxxxxxx </a></div> <div class="pt-1 pr-3 d-flex mt-auto bg-white position-relative"> <img class="position-relative" src="http://computervision.in/images/IN.png" height="50"> <img class="position-relative ml-3 mr-2" src="http://computervision.in/images/PV.png" height="55"> </div> </div> <div class="bottom d-flex w-100"> <a href="" class="navbar-brand mr-0"> <img src="http://computervision.in/images/logo.png" height="60"> </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 flex-grow-1 pl-4 position-relative"> <li class="nav-item active"><a class="nav-link text-white active" href="#">Home</a></li> <li class="nav-item"><a class="nav-link text-white" href="#">Services</a></li> <li class="nav-item"><a class="nav-link text-white" href="#">Courses</a></li> <li class="nav-item"><a class="nav-link text-white" href="#">Events</a></li> <li class="nav-item"><a class="nav-link text-white" href="#">Blogs</a></li> </ul> </div> </div> </nav> <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script> <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script> </body> </html> 

You just have to modify CSS as per your design. Hope this will work for you.