My code for a toggle button on the navbar using bootstrap4 is not displaying when the browser screen size is reduced. Can someone please help me identify what's wrong with my code?
<nav class="navbar navbar-expand-lg">
<button class="navbar-toggler " data-toggle="collapse" data-
target="#navbarcollapse">
<span class="navbar-toggler-icon" ></span>
</button>
<div class="collapse navbar-collapse" id="navbarcollapse">
<ul class ="navbar-nav mr-auto">
<li class="nav-item active"><a href="#"class="nav-link">Home</a></li>
<li><a href="#" class="nav-link">Services</a></li>
<li><a href="#"class="nav-link">Downloads</a></li>
<li><a href="#"class="nav-link">Projects</a></li>
<li><a href="#"class="nav-link">About Us</a></li>
<li><a href="#"class="nav-link">Contact</a></li>
</ul>
</div>
</nav>