var chapter_list = new Array(
  ["Vol.01 Ch.001: Tri-Edge","v01/c001"],
  ["Vol.01 Ch.002: The Lost Ones","v01/c002"],
  ["Vol.01 Ch.003: The Epitaph Users","v01/c003"],
  ["Vol.01 Ch.004: Endrance's Cat","v01/c004"],
  ["Vol.02 Ch.005: Avatar Awoken","v02/c005"],
  ["Vol.02 Ch.006: Serial Murder","v02/c006"],
  ["Vol.02 Ch.007: Logout Disabled","v02/c007"],
  ["Vol.02 Ch.008: Limits and Conflicts","v02/c008"],
  ["Vol.03 Ch.009: Atoli's World","v03/c009"],
  ["Vol.03 Ch.010: Things Fall Apart","v03/c010"],
  ["Vol.03 Ch.011: Aina","v03/c011"],
  ["Vol.03 Ch.012: Holy Ground -Key of Twilight-","v03/c012"],
  ["Vol.04 Ch.013: Letter from the Dead","v04/c013"],
  ["Vol.04 Ch.014: Security Section 2","v04/c014"],
  ["Vol.04 Ch.015: Xth Form","v04/c015"],
  ["Vol.04 Ch.016: R.A. Plan","v04/c016"],
  ["Vol.04 Ch.017: Sample","v04/c017"],
  ["Vol.04 Ch.018: False God","v04/c018"],
  ["Vol.05 Ch.019: Cubia","v05/c019"],
  ["Vol.05 Ch.020: Point of Origin","v05/c020"],
  ["Vol.05 Ch.021: The Shadowed One","v05/c021"],
  ["Vol.05 Ch.022: Foreboding","v05/c022"],
  ["Vol.05 Ch.023: Marching on the Brink","v05/c023"],
  ["Vol.05 Ch.024: The Visitor","v05/c024"],
  ["Vol.05 Ch.025: Anti Existence","v05/c025"],
  ["Vol.05 Ch.026: Reunion","v05/c026"]
);

var total_chapters = 26;

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;