var chapter_list = new Array(
  ["Vol.01 Ch.001: The Indulging Beast [Part 1]","v01/c001"],
  ["Vol.01 Ch.002: The Indulging Beast [Part 2]","v01/c002"],
  ["Vol.01 Ch.003: Stoic Desire","v01/c003"],
  ["Vol.01 Ch.004: Conflict of A Caged Bird ~ 1st Story","v01/c004"],
  ["Vol.01 Ch.005: Conflict of A Caged Bird ~ 2nd Story","v01/c005"],
  ["Vol.01 Ch.006: Conflict of A Caged Bird ~ 3rd Story","v01/c006"],
  ["Vol.01 Ch.007: Conflict of A Caged Bird ~ 4th Story & Extra ~ Indulgent Man (End)","v01/c007"]
);

var total_chapters = 7;

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;