<!DOCTYPE html>
<html>

  <head>
    <script data-require="jquery@*" data-semver="3.0.0" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.js"></script>
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body>
    <nav class="navbar navbar-inverse navbar-fixed-top" role="navigation">
      <div class="container" id="navbar"></div>
    </nav>
  </body>

</html>
$(document).ready(function() {
                $('#navbar').load('nav.html');
                });
/* Styles go here */

<div class="navbar-header">
  <span class="sr-only">Navegación</span>
  <span class="icon-bar"></span>
  <span class="icon-bar"></span>
  <span class="icon-bar"></span>
  <a class="navbar-brand" href="index.html">Nombre Empresa</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 navbar-right">
    <li>
      <a href="about.html">La Empresa</a>
    </li>
    <li>
      <a href="services.html">Servicios</a>
    </li>
    <li>
      <a href="contact.html">Contacto</a>
    </li>
    <li class="dropdown">
      <a href="#" class="dropdown-toggle" data-toggle="dropdown">Productos <b class="caret"></b></a>
      <ul class="dropdown-menu">
        <li>
          <a href="portfolio-1-col.html">1 Categoría 1</a>
        </li>
        <li>
          <a href="portfolio-2-col.html">2 Categoría 2</a>
        </li>
        <li>
          <a href="portfolio-3-col.html">3 Categoria 3</a>
        </li>
        <li>
          <a href="portfolio-4-col.html">4 Categoria 4</a>
        </li>
        <li>
          <a href="portfolio-item.html">Producto Item</a>
        </li>
      </ul>
    </li>
  </ul>
</div>