gistfile1.js

$(document).on('click', 'section.sets a.ajax', function() {
    var href = $(this).attr('href');
    $.ajax({
      url: href,
      success: function(data){
        console.log(data);
        $('section.sets div.items').append($(data).find('section.sets div.items').html());
        var href = $(data).find('section.sets a.ajax').attr('href');
        $('section.sets a.ajax').attr('href', href);
        $(window).on('scroll', onScroll);
      }
    });
    history.pushState({}, '', '/lookbook/');
    return false;
  });
  function onScroll(){
    if($(window).scrollTop() + $(window).height() > $(document).height() - 200) {
      $(window).off('scroll');
      $('section.sets a.ajax').trigger('click');
    }
  }
  $(window).scroll(onScroll);