<nav>
<ul>
<li><a href="#home">Домой</a></li>
<li><a href="#about">О нас</a></li>
</ul>
</nav>
<div id="home">
<!-- Some content -->
</div>
<div id="about">
<!-- Some content -->
</div>
<script type="text/javascript" src="https://code.jquery.com/jquery-2.1.3.min.js"></script>
<script>
$('nav a[href^="#"]').on('click', function() {
var target = $(this.hash);
$('html, body').clearQueue().animate({ scrollTop: target.offset().top }, 1500);
return false;
});
</script>