var chapter_list = new Array(
  ["Vol.01 Ch.001: Track 1","v01/c001"],
  ["Vol.01 Ch.002: Track 2","v01/c002"],
  ["Vol.01 Ch.003: Track 3","v01/c003"],
  ["Vol.01 Ch.004: Track 4","v01/c004"],
  ["Vol.02 Ch.001: Track 5","v02/c001"],
  ["Vol.02 Ch.002: Track 6","v02/c002"],
  ["Vol.02 Ch.003: Track 7","v02/c003"],
  ["Vol.02 Ch.004: Track 8","v02/c004"],
  ["Vol.03 Ch.001: Track 9","v03/c001"],
  ["Vol.03 Ch.002: Track 10","v03/c002"],
  ["Vol.03 Ch.003: Track 11","v03/c003"],
  ["Vol.03 Ch.004: Track 12","v03/c004"],
  ["Vol.04 Ch.001: Track 13","v04/c001"],
  ["Vol.04 Ch.002: Track 14","v04/c002"],
  ["Vol.04 Ch.003: Track 15","v04/c003"],
  ["Vol.04 Ch.004: Track 16","v04/c004"],
  ["Vol.05 Ch.001: Track 17","v05/c001"],
  ["Vol.05 Ch.002: Track 18","v05/c002"],
  ["Vol.05 Ch.003: Track 19","v05/c003"],
  ["Vol.05 Ch.004: Track 20","v05/c004"],
  ["Vol.05 Ch.005: Track 21","v05/c005"],
  ["Vol.06 Ch.001: Track 22","v06/c001"],
  ["Vol.06 Ch.002: Track 23","v06/c002"],
  ["Vol.06 Ch.003: Track 24","v06/c003"],
  ["Vol.06 Ch.004: Track 25","v06/c004"],
  ["Vol.06 Ch.005: Track 26","v06/c005"],
  ["Vol.07 Ch.001: Track 27","v07/c001"],
  ["Vol.07 Ch.002: Track 28","v07/c002"],
  ["Vol.07 Ch.003: Track 29","v07/c003"],
  ["Vol.07 Ch.004: Track 30","v07/c004"],
  ["Vol.07 Ch.005: Track  31","v07/c005"],
  ["Vol.08 Ch.001: Track 32","v08/c001"],
  ["Vol.08 Ch.002: Track 33","v08/c002"],
  ["Vol.08 Ch.003: Track 34","v08/c003"],
  ["Vol.08 Ch.004: Track 35","v08/c004"],
  ["Vol.08 Ch.005: Track 36","v08/c005"],
  ["Vol.09 Ch.001: Track 37","v09/c001"],
  ["Vol.09 Ch.002: Track 38","v09/c002"],
  ["Vol.09 Ch.003: Track 39","v09/c003"],
  ["Vol.09 Ch.004: Track 40","v09/c004"],
  ["Vol.09 Ch.005: Track 41","v09/c005"],
  ["Vol.10 Ch.001: Track 42","v10/c001"],
  ["Vol.10 Ch.002: Track 43","v10/c002"],
  ["Vol.10 Ch.003: Track 44","v10/c003"],
  ["Vol.10 Ch.004: Track 45","v10/c004"],
  ["Vol.10 Ch.004.1: Bonus Track","v10/c004.1"],
  ["Vol.11 Ch.001: Track 46","v11/c001"],
  ["Vol.11 Ch.002: Track 47","v11/c002"],
  ["Vol.11 Ch.003: Track 48","v11/c003"],
  ["Vol.11 Ch.003.1: Track 13651","v11/c003.1"],
  ["Vol.12 Ch.001: Track 49","v12/c001"],
  ["Vol.12 Ch.002: Track 50","v12/c002"],
  ["Vol.12 Ch.003: Track 51","v12/c003"],
  ["Vol.12 Ch.004: Track 52","v12/c004"],
  ["Vol.12 Ch.005: Track 53","v12/c005"],
  ["Vol.12 Ch.006: Track 54 (Final)","v12/c006"]
);

var total_chapters = 56;

for (var i = 0; i < chapter_list.length; i++) {
  document.getElementById('top_chapter_list').options[i] = new Option(chapter_list[i][0], chapter_list[i][1]);
  document.getElementById('bottom_chapter_list').options[i] = new Option(chapter_list[i][0], chapter_list[i][1]);
}
document.getElementById('top_chapter_list').value=current_chapter;
document.getElementById('bottom_chapter_list').value=current_chapter;
var current_chapter_index = document.getElementById('top_chapter_list').selectedIndex;