var chapter_list = new Array(
  ["Vol.01 Ch.001: Dancing Under the Crazy Moon","v01/c001"],
  ["Vol.01 Ch.002: Goodbye, My Friends, and Dear Enemy","v01/c002"],
  ["Vol.01 Ch.003: The School Carnival of Mad Children","v01/c003"],
  ["Vol.01 Ch.004: From Tears to Tears, Hell to Hell","v01/c004"],
  ["Vol.01 Ch.005: Angelic Bless to the Evanescent World","v01/c005"],
  ["Vol.01 Ch.006: Home","v01/c006"]
);

var total_chapters = 6;

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;