I have a menu that contains submenus. When the resolution is of mobile it only displays the menus and when I click on "products" it does not open the submenu that has in it, it is closed. What can it be?
<nav role="navigation" class="navbar">
<div class="navbar-header navbar-default">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#menu-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div id="menu-collapse" class="collapse navbar-collapse menu">
<ul>
<li><a href="<?php echo base_url();?>">Home</a></li>
<li><a href="<?php echo base_url('sobre');?>">Sobre nós</a></li>
<li><a href="<?php echo base_url('produtos');?>">Produtos</a>
<ul>
<?php echo dropdown();?>
</ul>
</li>
<li><a href="<?php echo base_url('contato');?>">Localização & Contato</a></li>
<li><a href="<?php echo base_url('orcamento');?>"><i class="fa fa-pencil-square-o"></i> Orçamento</a></li>
<li class="hidden-md hidden-lg">
<br />
<form action="<?php echo base_url('buscar');?>" method="post">
<input type="text" class="form-control search"name="buscar" placeholder="Buscar...">
</form>
</li>
</ul>
</div>
</nav>