var chap_array = new Array(
    ["10",'10'],

    ["9 - Yusura Falls in Love",'9'],

    ["8 - Yusura Departs",'8'],

    ["7 - Rival Arrival",'7'],

    ["6 - Wedding Bells for Yusura",'6'],

    ["5 - Wanna Meet a Monster",'5'],

    ["4 - Lost Comrade",'4'],

    ["3 - Eternal Friendship",'3'],

    ["2 - Brawl in the Bathhouse",'2'],

    ["1 - Yusura of Hikeshi-ya",'1']
);
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]);
    }
}