(function() {
  var track = document.querySelector('.carousel-track');
  if (!track) return;
  var dots = document.querySelectorAll('.carousel-dot');
  var caption = document.getElementById('carousel-caption');
  var captions = JSON.parse(caption.dataset.captions);
  var count = dots.length;
  var current = 0;
  function go(i) {
    current = i;
    track.style.transform = 'translateX(-' + (i * 100) + '%)';
    dots.forEach(function(d, j) { d.classList.toggle('active', j === i); });
    caption.textContent = captions[i];
  }
  dots.forEach(function(d) {
    d.addEventListener('click', function() { go(+d.dataset.index); });
  });
  setInterval(function() { go((current + 1) % count); }, 8000);
})();