var chap_array = new Array(
["Noridasu 11",'noridasu-11'],
["Noridasu 10",'noridasu-10'],
["Noridasu 9",'noridasu-9'],
["Noridasu 8",'noridasu-8'],
["Noridasu 7",'noridasu-7'],
["Noridasu 6",'noridasu-6'],
["Noridasu 5",'noridasu-5'],
["Noridasu 4",'noridasu-4'],
["Noridasu 3",'noridasu-3'],
["Noridasu 2",'noridasu-2'],
["Noridasu 1",'noridasu-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]);
}