// =======================================
// Functions for photo gallery page
// modified from code provided by Fabi
// =======================================
function changePhoto(photolist,photoimage) {
  var list = document.getElementById(photolist);
  var image = document.getElementById(photoimage);
  image.src = list.options[list.selectedIndex].value;
}
function prevPhoto(photolist,photoimage) {
  var list = document.getElementById(photolist);
  if(list.selectedIndex == 0) {
    list.selectedIndex = list.options.length-1;
  }
  else {
    list.selectedIndex--;
  }
  changePhoto(photolist,photoimage);
}
function nextPhoto(photolist,photoimage) { 
  var list = document.getElementById(photolist);
  if(list.selectedIndex == list.options.length-1) {
    list.selectedIndex = 0;
  }
  else {
    list.selectedIndex++;
  }
  changePhoto(photolist,photoimage);
}