var chapter_list = new Array(
  ["Vol.01 Ch.001: The Teacher's Office is Paradise on Earth","v01/c001"],
  ["Vol.01 Ch.002: Let's Meet After School","v01/c002"],
  ["Vol.01 Ch.003: A Drenched Out-of-Class Activity","v01/c003"],
  ["Vol.02 Ch.004: Must Be Love","v02/c004"],
  ["Vol.02 Ch.005: A Blooming Flower is the Prettiest of All","v02/c005"],
  ["Vol.02 Ch.006: Love Letter","v02/c006"],
  ["Vol.02 Ch.007: A Sky Filled with Stars","v02/c007"],
  ["Vol.02 Ch.008: Yesterday Today Tomorrow","v02/c008"],
  ["Vol.03 Ch.009: Love's Distance","v03/c009"],
  ["Vol.03 Ch.010: One Million Dollars Lady","v03/c010"],
  ["Vol.03 Ch.011: Stranger in the Night","v03/c011"],
  ["Vol.03 Ch.012: Love Nest","v03/c012"],
  ["Vol.03 Ch.013: Let's Both go HAA HAA (Final Chapter)","v03/c013"]
);

var total_chapters = 13;

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;