Do you really need that plugin? You can just animate the scrollTop
property:
$("#nav ul li a[href^='#']").on('click', function(e) {
// prevent default anchor click behavior
e.preventDefault();
// store hash
var hash = this.hash;
// animate
$('html, body').animate({
scrollTop: $(hash).offset().top
}, 300, function(){
// when done, add hash to url
// (default click behaviour)
window.location.hash = hash;
});
});