// If a Video is present in the previous slide, stop it.
    var s = $("section[aria-selected]");
    if (s) {
      var video = s.$("video");
      if (video) {
        if (video.ended || video.paused) {
          video.play();
        } else {
          video.pause();
        }
      }
    }
  }

  Dz.setCursor = function(aIdx, aStep) {
    // If the user change the slide number in the URL bar, jump
    // to this slide.
    aStep = (aStep != 0 && typeof aStep !== "undefined") ? "." + aStep : ".0";
    wi