Implement bootstrap header - html

Question

I have problems with implementing a bootstrap header in my code, but I think it's not my fault, but I dont know how to fix it.
The nav menu is always in phone view or something. I put my code in a JSFiddle so you guys can see my problem :
Here's the link: https://jsfiddle.net/wx86vq2y/2/
and I got a screenshot like how it had to be: https://gyazo.com/aca2e255638350dc386812ea9878ecfe . Does somewhone know what is wrong? I cant solve this problem at this moment.

Answer 1

<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarTogglerDemo01" aria-controls="navbarTogglerDemo01" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarTogglerDemo01">
<a class="navbar-brand" href="#">Dize Design AOS-Header v.2</a>
<ul class="navbar-nav mr-auto mt-2 mt-lg-0">
<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="#">Project</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">About Us</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="text" placeholder="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
you can solve it by replacing the beta version bootstrap 4 css to bootstrap 3 css bootstrap3 url
Please check the sample