var chapter_list = new Array(
  ["Vol.01 Ch.001: Let's Go","v01/c001"],
  ["Vol.01 Ch.002: Everything Lost","v01/c002"],
  ["Vol.01 Ch.003: The Hair Spray Trick","v01/c003"],
  ["Vol.01 Ch.004: Air Tank","v01/c004"],
  ["Vol.01 Ch.005: Dark Power","v01/c005"],
  ["Vol.01 Ch.006: Rao's Talisman","v01/c006"],
  ["Vol.01 Ch.007: Tank Battle","v01/c007"],
  ["Vol.01 Ch.008: General Shiba vs General Are","v01/c008"],
  ["Vol.01 Ch.009: Surprise in Sandstorm","v01/c009"],
  ["Vol.01 Ch.010: The Mystic Spring","v01/c010"],
  ["Vol.01 Ch.011: The Secret of the Mystic Spring","v01/c011"],
  ["Vol.01 Ch.012: Belzebub Supersrtar","v01/c012"],
  ["Vol.01 Ch.013: Judgement Day","v01/c013"],
  ["Vol.01 Ch.014: The River [end]","v01/c014"]
);

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;