function change_src(object, src) {
  if (document.getElementById) {
    document.getElementById(object).src = src;
  }

  else if (document.layers && document.layers[object] != null) {
    document.layers[object].src = src;
  }

  else if (document.all) {
    document.all[object].src = src;
  }

  return src;
}