var chapter_list = new Array(
  ["Vol.01 Ch.001: Who Killed Cock Robin?","v01/c001"],
  ["Vol.01 Ch.002: Rule of Rule","v01/c002"],
  ["Vol.01 Ch.003: Dying Happy Dog Race","v01/c003"],
  ["Vol.01 Ch.004: Slayer's Slave","v01/c004"],
  ["Vol.02 Ch.005: Necro Macro","v02/c005"],
  ["Vol.02 Ch.006: Crow Craw","v02/c006"],
  ["Vol.02 Ch.007: Carnival Corpse","v02/c007"],
  ["Vol.02 Ch.008: Bloodthirsty Majesty","v02/c008"],
  ["Vol.03 Ch.009: Liar Flower","v03/c009"],
  ["Vol.03 Ch.010: Big Bad Bingo","v03/c010"],
  ["Vol.03 Ch.011: Past Time, Tight End","v03/c011"],
  ["Vol.03 Ch.012: Scar Chain","v03/c012"],
  ["Vol.04 Ch.013: Cloudy After Sunny","v04/c013"],
  ["Vol.04 Ch.014: Ring Her Bell","v04/c014"],
  ["Vol.04 Ch.015: Man is the Archenemy for man","v04/c015"],
  ["Vol.04 Ch.016: Salty Cookies","v04/c016"],
  ["Vol.05 Ch.017: Loser's Answer","v05/c017"],
  ["Vol.05 Ch.018: Chain Gang","v05/c018"],
  ["Vol.05 Ch.019: Bloody rainy day","v05/c019"],
  ["Vol.05 Ch.020: Relief to Nirvana","v05/c020"],
  ["Vol.05 Ch.021: Ghost in the Sun","v05/c021"],
  ["Vol.05 Ch.022: Tongue and Every Day","v05/c022"],
  ["Vol.05 Ch.023: The Fake Face","v05/c023"],
  ["Vol.05 Ch.024: Anger Song, Under Peace","v05/c024"],
  ["Vol.05 Ch.025: Failure firing","v05/c025"]
);

var total_chapters = 25;

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;