bootstrap collapsible navbar right and left side code example

Example 1: dissect the navbar bootstrap

<h1><a name="responsivebtn"></a>A responsive navigation bar with toggle button</h1>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent_resptb" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
    </button>
    <div class="collapse navbar-collapse" id="navbarSupportedContent_resptb">
        <div class="navbar-nav">
            <a class="nav-item nav-link active" href="#">Item1 Active</span></a>
            <a class="nav-item nav-link" href="#">Item2</a>
            <a class="nav-item nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Item3 Disabled</a>
        </div>
    </div>
</nav>

Example 2: bootstrap bar

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNavAltMarkup">
    <div class="navbar-nav">
      <a class="nav-item nav-link active" href="#">Home <span class="sr-only">(current)</span></a>
      <a class="nav-item nav-link" href="#">Features</a>
      <a class="nav-item nav-link" href="#">Pricing</a>
      <a class="nav-item nav-link disabled" href="#">Disabled</a>
    </div>
  </div>
</nav>