How to enable the dropdown element in bootstrap? - html

Question

I am a newbie to bootstrap and now I wish to use its navbar and dropdown elements. When I copied the code of its example (see below) and click on the dropdown element, the expected dropdown menu doesn't appear, which is different with its original page. Could you please tell me how to enable it? Thanks!
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"> </script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" crossorigin="anonymous">
<div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Brand</a>
</div>
<!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav">
<li class="active">Link <span class="sr-only">(current)</span></li>
<li>Link</li>
<li class="dropdown">
Dropdown <span class="caret"></span>
<ul class="dropdown-menu">
<li>Action</li>
<li>Another action</li>
<li>Something else here</li>
<li role="separator" class="divider"></li>
<li>Separated link</li>
<li role="separator" class="divider"></li>
<li>One more separated link</li>
</ul>
</li>
</ul>
<form class="navbar-form navbar-left" role="search">
<div class="form-group">
<input type="text" class="form-control" placeholder="Search">
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<ul class="nav navbar-nav navbar-right">
<li>Link</li>
<li class="dropdown">
Dropdown <span class="caret"></span>
<ul class="dropdown-menu">
<li>Action</li>
<li>Another action</li>
<li>Something else here</li>
<li role="separator" class="divider"></li>
<li>Separated link</li>
</ul>
</li>
</ul>
</div><!-- /.navbar-collapse -->
</div><!-- /.container-fluid -->
</nav>

Answer 1

You have wrong order of javascript files, Bootstrap requires jQuery, just change order
<!-- FIRST jquery -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"> </script>
<!-- THEN bootstrap -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" crossorigin="anonymous"></script>
Next time take a look into developer console of your browser, bootstrap prints error message when jQuery isn't present
bootstrap.min.js:6 Uncaught Error: Bootstrap's JavaScript requires
jQuery
You may also want to take a look at the W3C html validator, it will let you know about html errors in your syntax, you will find out that there is no opening tag for nav (as #LeoTheLion has pointed out)

Answer 2

You are missing nav tag.
Add this <nav class="navbar navbar-default">
as you have closed but did not started so.
See here

Answer 3

You need this scripts:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>