anchor.diff:  
       var post_frame = this.post_frames[post_idx];
       var url;
  -    if(post_frame != -1)
  +    if(post_frame !== -1)
         url = post.frames[post_frame].preview_url;
       else
         url = post.preview_url;
  
positive.code:   }
  
    var li = $(event.target).up(".post-thumb");
    if(li == null)
      return;
  
    /* An actual thumbnail was clicked.  This can happen if we don't have the expanded
  
negative.code:      */
      var post_id_search_order = sort_array_by_distance(old_post_ids.slice(0, old_centered_post_idx+3), old_centered_post_idx);
      var initial_post_id = null;
      for(i = 0; i < post_id_search_order.length; ++i)
      {
        var post_id_to_search = post_id_search_order[i];
        post = Post.posts.get(post_id_to_search);
        if(post !== null && post !== undefined)
        {
          initial_post_id = post.id;
          break;
  