Bootstrap 4 - 响应式导航栏不会崩溃

Question

When on mobile, the collapsible navbar is open and even when clicking the hamburger button, the navbar does not collapse. After looking at multiple examples and doing research, I can't find what I am forgeting. I included the "collapse" and "navbar-collapse" classes to the navbar links div.

  <nav class="navbar navbar-dark navbar-expand-md fixed-top" style="background-color: #9D0B0F;"> <!-- Navbar --> <div class="container"> <!-- Container (navbar content) --> <div class="navbar-brand"><a href="index.php"><img src="images/full_logo_white.png" alt="CeTSC Logo" style="height:40px;"/></a></div> <!-- CeTSC logo --> <!-- Hamburger button, only visible when open on mobile device --> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#myToggleNav" aria-controls="myToggleNav" aria-expanded="false" aria-label="Toggle Navigation"><span class="navbar-toggler-icon"></span></button> <div class="collapse navbar-collapse justify-content-end navbar-nav" id="myToggleNav"> <!-- Navbar links --> <div class="dropdown"> <!-- About dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="aboutDropdown" href="#">About</a> <!-- Link to about dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- About dropdown menu --> <a class="dropdown-item" href="#">Who we are</a> <!-- Link to who we are page --> <a class="dropdown-item" href="#">Our team</a> <!-- Link to our team page --> </div> <!-- About dropdown menu --> </div> <!-- About dropdown --> <div class="dropdown"> <!-- Shop dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="shopDropdown" href="#">Shop</a> <!-- Link to shop dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- Shop dropdown menu --> <a class="dropdown-item" href="#">Lockers</a> <!-- Link to lockers page --> <a class="dropdown-item" href="#">Merch</a> <!-- Link to merch page --> </div> <!-- Shop dropdown menu --> </div> <!-- Shop dropdown --> <a class="nav-item nav-link mx-lg-3" href="#">Sponsorship</a> <!-- Link to sponsorship page --> <div class="dropdown"> <!-- Get involved dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="getInvolvedDropdown" href="#">Get involved</a> <!-- Link to get involved dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- Get involved dropdown menu --> <a class="dropdown-item" href="#">Join our team</a> <!-- Link to join our team page --> <a class="dropdown-item" href="#">Initiatives</a> <!-- Link to initiatives page --> <a class="dropdown-item" href="#">ECP</a> <!-- Link to ECP page --> </div> <!-- Get involved dropdown menu --> </div> <!-- Get involved dropdown --> <a class="nav-item nav-link mx-lg-3" href="#">Clubs</a> <!-- Link to clubs page --> <a class="nav-item nav-link mx-lg-3" href="contact.php">Contact</a> <!-- Link to contact page --> </div> <!-- Navbar links --> </div> <!-- Container (navbar content) --> </nav> <!-- Navbar --> 

Answer 1

The class navbar-nav is incompatible with the combination of collapse and navbar-collapse ; you have to use one or the other.

To fix this problem, simply remove the navbar-nav class on your content:

 <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-dark navbar-expand-md fixed-top" style="background-color: #9D0B0F;"> <!-- Navbar --> <div class="container"> <!-- Container (navbar content) --> <div class="navbar-brand"> <a href="index.php"><img src="images/full_logo_white.png" alt="CeTSC Logo" style="height:40px;" /></a> </div> <!-- CeTSC logo --> <!-- Hamburger button, only visible when open on mobile device --> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#myToggleNav" aria-controls="myToggleNav" aria-expanded="false" aria-label="Toggle Navigation"><span class="navbar-toggler-icon"></span></button> <div class="collapse navbar-collapse justify-content-end" id="myToggleNav"> <!-- Navbar links --> <div class="dropdown"> <!-- About dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="aboutDropdown" href="#">About</a> <!-- Link to about dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- About dropdown menu --> <a class="dropdown-item" href="#">Who we are</a> <!-- Link to who we are page --> <a class="dropdown-item" href="#">Our team</a> <!-- Link to our team page --> </div> <!-- About dropdown menu --> </div> <!-- About dropdown --> <div class="dropdown"> <!-- Shop dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="shopDropdown" href="#">Shop</a> <!-- Link to shop dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- Shop dropdown menu --> <a class="dropdown-item" href="#">Lockers</a> <!-- Link to lockers page --> <a class="dropdown-item" href="#">Merch</a> <!-- Link to merch page --> </div> <!-- Shop dropdown menu --> </div> <!-- Shop dropdown --> <a class="nav-item nav-link mx-lg-3" href="#">Sponsorship</a> <!-- Link to sponsorship page --> <div class="dropdown"> <!-- Get involved dropdown --> <a class="nav-item nav-link mx-lg-3 dropdown-toggle" data-toggle="dropdown" id="getInvolvedDropdown" href="#">Get involved</a> <!-- Link to get involved dropdown menu --> <div class="dropdown-menu rounded-0" style="border-color: #9D0B0F;"> <!-- Get involved dropdown menu --> <a class="dropdown-item" href="#">Join our team</a> <!-- Link to join our team page --> <a class="dropdown-item" href="#">Initiatives</a> <!-- Link to initiatives page --> <a class="dropdown-item" href="#">ECP</a> <!-- Link to ECP page --> </div> <!-- Get involved dropdown menu --> </div> <!-- Get involved dropdown --> <a class="nav-item nav-link mx-lg-3" href="#">Clubs</a> <!-- Link to clubs page --> <a class="nav-item nav-link mx-lg-3" href="contact.php">Contact</a> <!-- Link to contact page --> </div> <!-- Navbar links --> </div> <!-- Container (navbar content) --> </nav> <!-- Navbar -->