var chapter_list = new Array(
  ["Vol.01 Ch.001: The Evil One","v01/c001"],
  ["Vol.01 Ch.002: Prince","v01/c002"],
  ["Vol.01 Ch.003: Little Sparrow","v01/c003"],
  ["Vol.01 Ch.004: Coward","v01/c004"],
  ["Vol.01 Ch.005: Wolves","v01/c005"],
  ["Vol.01 Ch.006: Enemies","v01/c006"],
  ["Vol.01 Ch.007: Brother","v01/c007"],
  ["Vol.01 Ch.008: Voice of Jade","v01/c008"],
  ["Vol.02 Ch.009: Alfald","v02/c009"],
  ["Vol.02 Ch.010: Raid","v02/c010"],
  ["Vol.02 Ch.011: Lullaby","v02/c011"],
  ["Vol.02 Ch.012: Gates","v02/c012"],
  ["Vol.02 Ch.013: Darkness","v02/c013"],
  ["Vol.02 Ch.014: Writings","v02/c014"],
  ["Vol.02 Ch.015: Poisoned Blade","v02/c015"],
  ["Vol.03 Ch.016: Bow and Arrow","v03/c016"],
  ["Vol.03 Ch.017: Exultation","v03/c017"],
  ["Vol.03 Ch.018: Separation","v03/c018"],
  ["Vol.03 Ch.019: Execution","v03/c019"],
  ["Vol.03 Ch.020: Heartbeat","v03/c020"],
  ["Vol.03 Ch.021: Miracles","v03/c021"],
  ["Vol.03 Ch.022: The Academy","v03/c022"],
  ["Vol.04 Ch.023: Xixia's words","v04/c023"],
  ["Vol.04 Ch.024: Ifa","v04/c024"]
);

var total_chapters = 24;

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;