function youtube_deliver(video_id) {
   $('.youtube_index_item').removeClass('youtube_index_selected');
   $('#youtube_index_item_' + video_id).addClass('youtube_index_selected');
   $('#youtube_content').html($('#content_' + video_id).html());
}

function list_youtube_index() {
  var index_html = "<strong>Video:</strong> ";  
  var counter = 0;
  $('.youtube_list_item').each(function() {
    counter += 1;
    var youtube_id = this.id.replace('youtube_list_item_', '');
    index_html += "<a class='youtube_index_item' id='youtube_index_item_" + youtube_id + "' href=\"javascript:youtube_deliver('" + youtube_id + "');\">" + counter + "</a>";

  });
  $('#youtube_index').html(index_html);  
}