Bouton de scroll [HTML, CSS , jQuery]

 <a href="#" style="position: fixed; top: 10px">Cliquez ici</a>
<div style="height: 10000px"></div>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7/jquery.min.js"></script>
<script>
    $('a').click(function(event){
            event.preventDefault();
            var positionScroll = 1500;
            $('body').animate({scrollTop: positionScroll}, 500);
     });
</script>