var chap_array = new Array(
["Nana To Kaoru 20",'nana-to-kaoru-20'],
["Nana To Kaoru 19",'nana-to-kaoru-19'],
["Nana To Kaoru 18",'nana-to-kaoru-18'],
["Nana To Kaoru 17",'nana-to-kaoru-17'],
["Nana To Kaoru 16",'nana-to-kaoru-16'],
["Nana To Kaoru 15",'nana-to-kaoru-15'],
["Nana To Kaoru 14",'nana-to-kaoru-14'],
["Nana To Kaoru 13",'nana-to-kaoru-13'],
["Nana To Kaoru 12",'nana-to-kaoru-12'],
["Nana To Kaoru 11",'nana-to-kaoru-11'],
["Nana To Kaoru 10",'nana-to-kaoru-10'],
["Nana To Kaoru 9",'nana-to-kaoru-9'],
["Nana To Kaoru 8",'nana-to-kaoru-8'],
["Nana To Kaoru 7",'nana-to-kaoru-7'],
["Nana To Kaoru 6",'nana-to-kaoru-6'],
["Nana To Kaoru 5",'nana-to-kaoru-5'],
["Nana To Kaoru 4",'nana-to-kaoru-4'],
["Nana To Kaoru 3",'nana-to-kaoru-3'],
["Nana To Kaoru 2",'nana-to-kaoru-2'],
["Nana To Kaoru 1",'nana-to-kaoru-1']);

for (var i=0; i<chap_array.length; i++) {
document.getElementById('chapter_select').options[i] = new Option(chap_array[i][0],chap_array[i][1]);
}