How to make a collapsed menu on resolution change?

Question

Web servers

There is a simple menu, when the resolution is changed to 960, the login and registration buttons disappear, how can I make a collapsed menu?

<nav class="navbar navbar-default navbar-static-top">
            <div class="container">
            <div class="navbar-header">
                <a class="navbar-brand logo" href="{% url 'index' %}">
                    <img alt="Brand" src="{% static '/logo2.png' %}">
                </a>
            </div>
            <div class="collapse navbar-collapse">
               <ul class="nav navbar-nav navbar-right">
                   <li><a href="{% url 'register' %}" data-toggle="modal" data-target="#myModal" data-modal-callback="reload">Регистрация</a></li>
                   <li><a href="/accounts/login">Войти</a></li>
            </div></div></nav>

Answer 1

<div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Brand</a>
    </div>