var chap_array = new Array(
["Baroque 5",'baroque-5'],
["Baroque 4",'baroque-4'],
["Baroque 3",'baroque-3'],
["Baroque 2",'baroque-2'],
["Baroque 1",'baroque-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]);
}