When you want to highlight a navigation anchor with scrollTo

jquery.scrollTo.and.highlight.anchor.js

$(document).ready(function() {
  $('nav.primary a').click(function(event) { // the elements you click to scroll
    event.preventDefault();
    var link = this; // you need this if you are using hash links on ex: a href="#link" to id="link"
    $.smoothScroll({
      offset: -160, // adjusts where the scroll will stop so the height of the scrolling element plus the height of the element you are scrolling to.
      speed: 2000,
      scrollTarget: link.hash
    });
  });
  // waypoint alternative
  // jsfiddle.net/senff/4D3bH/3/
  $('nav.primary a').click(function(){
    $('nav.primary a').removeClass('active');
    $(this).addClass('active');
  });
});