var activeBooks = new Array(7);
var inactiveBooks = new Array(7);
var x = 1;
for (x = 1; x <=7; x++) {
  activeBooks[x] = new Image();
  activeBooks[x].src = './images/trimmed/non' + x + '.jpg';
  inactiveBooks[x] = new Image();
  inactiveBooks[x].src = './images/trimmed/non' + x + '.jpg';
}
function activate (index,bookid) {
    document[bookid].src = activeBooks[index].src;
}
function inactivate (index,bookid) {
    document[bookid].src = inactiveBooks[index].src;
}