SublimeVideo: Interactive thumbnails JavaScript code (Prototype)

gistfile1.js

var SublimeVideo = SublimeVideo || {};

var InteractiveThumbnailsHandler = Class.create({
  initialize: function(interactiveWrapperId) {
    this.interactiveWrapperId = interactiveWrapperId;
    this.videosCount = $$("#" + interactiveWrapperId + " .video_wrap").size();

    $$("#" + this.interactiveWrapperId + " li").each(function(thumb) {
      thumb.on("click", function(event) {
        event.stop();
        if (!thumb.hasClassName("active")) {
          this.clickOnThumbnail(thumb.readAttribute("id"));
        }
      }.bind(this));
    }.bind(this));

    sublimevideo.ready(function() {
      sublimevideo.onEnd(function(sv) {
        var matches = sv.element.id.match(/^video(\d+)$/);
        if (matches != undefined) {
          if (parseInt(matches[1], 10) <= this.videosCount) {
            this.handleAutoNext(sv.element.id);
          }
        }
      }.bind(this));
    }.bind(this));

    this.loadDemo();
  },
  loadDemo: function() {
    // Only if not the first time here
    if (this.activeVideoId) this.reset();

    this.activeVideoId = "video1";

    // Show first video
    this.showActiveVideo(this.activeVideoId);
  },
  reset: function() {
    // Hide the current active video
    $$("#" + interactiveWrapperId + " .video_wrap.active").first().removeClassName("active");

    // Get current active video and unprepare it
    // we could have called sublimevideo.unprepare() without any arguments, but this is faster
    sublimevideo.unprepare(this.activeVideoId);

    // Deselect its thumbnail
    this.deselectThumbnail(this.activeVideoId);
  },
  clickOnThumbnail: function(thumbnailId) {
    // Basically undo all the stuff and bring it back to the point before js kicked in
    this.reset();

    // Set the new active video ...
    this.activeVideoId = thumbnailId.replace(/^thumbnail_/, "");

    // Show it ...
    this.showActiveVideo(this.activeVideoId);

    // And finally, prepare and play it
    sublimevideo.prepareAndPlay(this.activeVideoId);
  },
  selectThumbnail: function(videoId) {
    $("thumbnail_" + videoId).addClassName("active");
  },
  deselectThumbnail: function(videoId) {
    $("thumbnail_" + videoId).removeClassName("active");
  },
  showActiveVideo: function(videoId) {
    // Show it
    $(this.activeVideoId).up().addClassName("active");

    // Select its thumb
    this.selectThumbnail(this.activeVideoId);
  },
  handleAutoNext: function(endedVideoId) {
    var nextId = parseInt(endedVideoId.replace(/^video/, ""), 10) + 1;
    if (nextId > 1 && nextId <= this.videosCount) {
      this.clickOnThumbnail("thumbnail_video" + nextId);
    }
  }
});

document.observe("dom:loaded", function() {
  // Pass in the id of the interactive wrapper div
  SublimeVideo.interactiveThumbnails = new InteractiveThumbnailsHandler("interactive");
});