var chapter_list = new Array(
  ["Vol.01 Ch.000: Prologue","v01/c000"],
  ["Vol.01 Ch.001: Rokkenjima","v01/c001"],
  ["Vol.01 Ch.002: The Legend of the Witch","v01/c002"],
  ["Vol.01 Ch.003: Umineko no Naku Koro ni","v01/c003"],
  ["Vol.01 Ch.004: The Golden Inscription","v01/c004"],
  ["Vol.01 Ch.005: Letter from the Witch","v01/c005"],
  ["Vol.02 Ch.006: Eternal Promise","v02/c006"],
  ["Vol.02 Ch.007: The First Twilight 1","v02/c007"],
  ["Vol.02 Ch.008: The First Twilight 2","v02/c008"],
  ["Vol.02 Ch.009: The Witch's Sacrifices","v02/c009"],
  ["Vol.02 Ch.010: The Formless Witch","v02/c010"],
  ["Vol.02 Ch.011: The Invisible Witch","v02/c011"],
  ["Vol.02 Ch.012: Eva vs Natsuhi","v02/c012"],
  ["Vol.03 Ch.013: Battler vs Eva","v03/c013"],
  ["Vol.03 Ch.014: The Second Night 1","v03/c014"],
  ["Vol.03 Ch.015: The Second Night 2","v03/c015"],
  ["Vol.03 Ch.016: Kanon vs Beatrice","v03/c016"]
);

var total_chapters = 17;

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;