var chap_array = new Array(
    ["16 - Last Quarter",'16/01'],

    ["15 - Over",'15/01'],

    ["14 - Heaven",'14/01'],

    ["13 - Wish",'13/01'],

    ["12 - Fault",'12/01'],

    ["11 - Sayaka",'11/01'],

    ["10 - True",'10/01'],

    ["9 - Remember",'9/01'],

    ["8 - Life",'8/01'],

    ["7 - Stay",'7/01'],

    ["6 - Key",'6/00'],

    ["5 - Eve",'5/01'],

    ["4 - Ring",'4/01'],

    ["3 - Cross",'3/01'],

    ["2 - Border",'2/01'],

    ["1 - Mizuki",'1/00']
);
for (var i=0; i<chap_array.length; i++) {
    document.getElementById('id_chapter_1').options[i] = new Option(chap_array[i][0],chap_array[i][1]);
    if (document.getElementById('id_chapter_2')) {
        document.getElementById('id_chapter_2').options[i] = new Option(chap_array[i][0],chap_array[i][1]);
    }
}