var chap_array = new Array(
    ["18 - Top of the World",'18'],

    ["17 - Best of Both Worlds",'17'],

    ["16 - Dreams",'16'],

    ["15 - Everyone Wants Some!!",'15'],

    ["14 - Feel Your Love Tonight",'14'],

    ["13 - I'll Wait",'13'],

    ["12 - And the Craddle will Rock",'12'],

    ["11 - Unchained",'11'],

    ["10 - When It's Love",'10'],

    ["9 - Why Can't This Be Love",'9'],

    ["8 - Can't Stop Lovin You",'8'],

    ["7 - Ain't Talkin' Bout Love",'7'],

    ["6 - Runnin' With The Devil",'6'],

    ["5 - Dance The Night Away",'5'],

    ["4 - You Really Got Me",'4'],

    ["3 - Eruption",'3'],

    ["2 - Hot For Teacher",'2'],

    ["1 - Oh, Pretty Woman",'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]);
    }
}