Bootstrap drop down feature is not working - html

Question

Need help to resolve the bootstrap dropdown navigation issue. I followed all the rules available but I am missing something. Please help.
The service tab has two drop down li which should open when click on the caret. But the website css is not allowing to do so.
<!-- navbar-header -->
<div class="header-nav">
<nav class="navbar navbar-default">
<div class="navbar-header logo">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<h1>
<a class="navbar-brand" href="http://www.example.com/">Brand Name</a>
</h1>
</div>
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1 navis">
<ul class="nav navbar-nav navbar-right">
<li>Home</li>
<li>About</li>
<li class="dropdown">
</span>
<ul class="dropdown-menu">
<li>SEO Service</li>
<li>Digital Marketing</li>
</ul>
</li>
<li>Projects</li>
<li>Timeline</li>
<li>Contact</li>
</ul>
</div>
<div class="contact-bnr-w3-agile">
<ul>
<!--<li><i class="fa fa-envelope" aria-hidden="true"></i>info#example.com</li>-->
<li><i class="fa fa-phone" aria-hidden="true"></i>000000000 </li>
</ul>
</div>
<div class="clearfix"> </div>
</nav>
<div class="clearfix"> </div>
</div>

Answer 1

You have a typo in your code:
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
Here, data-target represents the div that is being targeted for toggling when you click the button. So, it is looking for the div with the ID "bs-example-navbar-collapse-1". This line is fine, though I'd recommend renaming it to something more useful, like "site-nav" or something.
Now, here is where the problem occurs:
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1 navis">
This is the div that you are (correctly) trying to expand/collapse. But you have given it the id "bs-example-navbar-collapse-1 navis", which is not the same as "bs-example-navbar-collapse-1". So, you are clicking the button, but no div is being found with a matching ID.
To solve this, set the ID to "bs-example-navbar-collapse-1" instead (remove "navis"):
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
Now, all should be right in the world.
Also, far as the jQuery warnings mentioned above, it seems you are loading jQuery 2 already, so you don't need to include 1.12 as well. So make sure you are including the jQuery lib that you want.