var chap_array = new Array(
["After School Nightmare 2",'after-school-nightmare-2'],
["After School Nightmare 1",'after-school-nightmare-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]);
}