if (document.images) {
// These are for the navigation button rollovers.
  cartHomeOn = new Image();
  cartHomeOn.src = "/images/nav/nav_cart_home_over.gif";
  cartHomeOff = new Image();
  cartHomeOff.src = "/images/nav/nav_cart_home.gif";
  cartBooksOn = new Image();
  cartBooksOn.src = "/images/nav/nav_cart_books_over.gif";
  cartBooksOff = new Image();
  cartBooksOff.src = "/images/nav/nav_cart_books.gif";
  cartNewsOn = new Image();
  cartNewsOn.src = "/images/nav/nav_cart_news_over.gif";
  cartNewsOff = new Image();
  cartNewsOff.src = "/images/nav/nav_cart_news.gif";
  cartSubmissionsOn = new Image();
  cartSubmissionsOn.src = "/images/nav/nav_cart_submissions_over.gif";
  cartSubmissionsOff = new Image();
  cartSubmissionsOff.src = "/images/nav/nav_cart_submissions.gif";
  cartContactOn = new Image();
  cartContactOn.src = "/images/nav/nav_cart_contact_over.gif";
  cartContactOff = new Image();
  cartContactOff.src = "/images/nav/nav_cart_contact.gif";
}