var chapter_list = new Array(
  ["Vol.01 Ch.001","v01/c001"],
  ["Vol.01 Ch.002: "Again?"","v01/c002"],
  ["Vol.01 Ch.003: Explain It One More Time!!","v01/c003"],
  ["Vol.01 Ch.004: When You Think You Can Pay Back, It's Already Over","v01/c004"],
  ["Vol.01 Ch.004.5: [Extras]","v01/c004.5"],
  ["Vol.02 Ch.005: And Life Goes On","v02/c005"],
  ["Vol.02 Ch.006: Nothing Can Kill My Happiness!","v02/c006"],
  ["Vol.02 Ch.007: The Beginning Which Leads to the End of All","v02/c007"],
  ["Vol.02 Ch.008: A Man Has to Take Responsibility","v02/c008"],
  ["Vol.03 Ch.009: Under Pressure!!","v03/c009"],
  ["Vol.03 Ch.010: Burning Everything!","v03/c010"],
  ["Vol.03 Ch.011: Are You Serious?","v03/c011"],
  ["Vol.03 Ch.012: So, What Now?!","v03/c012"],
  ["Vol.03 Ch.012.5: [Extra]","v03/c012.5"],
  ["Vol.04 Ch.013","v04/c013"],
  ["Vol.04 Ch.014","v04/c014"],
  ["Vol.04 Ch.015","v04/c015"],
  ["Vol.04 Ch.016","v04/c016"],
  ["Vol.04 Ch.016.5: [Extra]","v04/c016.5"],
  ["Vol.05 Ch.017: Land of Warlord","v05/c017"],
  ["Vol.05 Ch.018","v05/c018"],
  ["Vol.05 Ch.019","v05/c019"],
  ["Vol.05 Ch.020","v05/c020"],
  ["Vol.05 Ch.020.5","v05/c020.5"]
);

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;