function randomBackground() {
  random_number = randomNumber();
  background_img = 'images/filigree-' + random_number + '.gif'
  $('layout_container').style.background = "white url('" + background_img + "') no-repeat left bottom";
}

function randomNumber() {
  return Math.floor(Math.random() * (3 - 0)) + 1;
}