jSmooth.js

$(function() {
	$('a.page-scroll').bind('click', function(event) {
		var $anchor = $(this);
		
		//This implementation requires JQueryEasing plugin to work [http://cdnjs.cloudflare.com/ajax/libs/jquery-easing/1.3/jquery.easing.min.js]
		$('html, body').stop().animate({
		  scrollTop: $($anchor.attr('href')).offset().top - 90
		}, 1500, 'easeInOutExpo');

	  	$(this).parents('.nav-container').find('.active').removeClass('active').end().end().addClass('active');
	  	event.preventDefault();
	});

	$(window).scroll(function(){
		var whatWeDo 	= $("#what-we-do"),
			whoWeWeAre 	= $("#who-we-are"),
			ourWork 	= $("#our-work"),
			connect		= $("#connect");

  		if($(window).scrollTop() >= ( whatWeDo.offset().top - 90) ){
  			$('.nav-container').find('a[href="#what-we-do"]').parents('.nav-container').find('.active').removeClass('active').end().end().addClass('active');
  		}
  		if($(window).scrollTop() >= ( whoWeWeAre.offset().top - 90) ){
  			$('.nav-container').find('a[href="#who-we-are"]').parents('.nav-container').find('.active').removeClass('active').end().end().addClass('active');
  		}
  		if($(window).scrollTop() >= ( ourWork.offset().top - 90) ){
  			$('.nav-container').find('a[href="#our-work"]').parents('.nav-container').find('.active').removeClass('active').end().end().addClass('active');
  		}
  		if($(window).scrollTop() >= ( connect.offset().top - 90) ){
  			$('.nav-container').find('a[href="#connect"]').parents('.nav-container').find('.active').removeClass('active').end().end().addClass('active');
  		}
  	});
});