var chapter_list = new Array(
  ["Vol.01 Ch.001","v01/c001"],
  ["Vol.01 Ch.002","v01/c002"],
  ["Vol.01 Ch.003","v01/c003"],
  ["Vol.01 Ch.004","v01/c004"],
  ["Vol.01 Ch.004.5: Omake","v01/c004.5"],
  ["Ch.014","c014"],
  ["Ch.015","c015"],
  ["Ch.016","c016"],
  ["Ch.016.5","c016.5"],
  ["Ch.017","c017"],
  ["Ch.018","c018"],
  ["Ch.019","c019"],
  ["Vol.02 Ch.005","v02/c005"],
  ["Vol.02 Ch.006","v02/c006"],
  ["Vol.02 Ch.007","v02/c007"],
  ["Vol.02 Ch.008","v02/c008"],
  ["Vol.02 Ch.009","v02/c009"],
  ["Vol.03 Ch.010","v03/c010"],
  ["Vol.03 Ch.011","v03/c011"],
  ["Vol.03 Ch.012","v03/c012"],
  ["Vol.03 Ch.013","v03/c013"],
  ["Vol.04 Ch.014","v04/c014"],
  ["Vol.04 Ch.015: Zettai Heiwa Daisakusen 15","v04/c015"],
  ["Vol.04 Ch.016: Zettai Heiwa Daisakusen 16","v04/c016"],
  ["Vol.04 Ch.016.5: Zettai Heiwa Daisakusen 16.5 Omake","v04/c016.5"],
  ["Vol.05 Ch.017: Zettai Heiwa Daisakusen 17","v05/c017"],
  ["Vol.05 Ch.018: Zettai Heiwa Daisakusen 18","v05/c018"],
  ["Vol.05 Ch.019: Zettai Heiwa Daisakusen 19 END","v05/c019"]
);

var total_chapters = 28;

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;