"

From 2013.igem.org

var offsetHeight = 331;

$('.nav-collapse').scrollspy({

   offset: offsetHeight

});

$('.nav li a').click(function (event) {

   var scrollPos = $('html').find($(this).attr('href')).offset().top - offsetHeight;
   $('body,html').animate({
       scrollTop: scrollPos
   }, 1000);
   return false;

});