var chapter_list = new Array(
  ["Vol.01 Ch.001","v01/c001"],
  ["Vol.01 Ch.002: Full Stomach Pot","v01/c002"],
  ["Vol.01 Ch.003","v01/c003"],
  ["Vol.01 Ch.004","v01/c004"],
  ["Vol.01 Ch.005","v01/c005"],
  ["Vol.01 Ch.006","v01/c006"],
  ["Vol.02 Ch.001: Memories","v02/c001"],
  ["Vol.02 Ch.002: A Promise","v02/c002"],
  ["Vol.02 Ch.003: Farewell Vexen","v02/c003"],
  ["Vol.02 Ch.004: Separated Hearts","v02/c004"],
  ["Vol.02 Ch.005: Shock!!!","v02/c005"],
  ["Vol.02 Ch.006: Where the Heart Leads","v02/c006"],
  ["Vol.02 Ch.007: The Road at Dawn - End","v02/c007"],
  ["Vol.02 Ch.013: Dawning Path","v02/c013"]
);

var total_chapters = 14;

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;