function preloadTopMenu() {
  var img = new Image();
  img.src = "/webmail/images/top_new_message_over.gif";
  img = new Image();
  img.src = "/webmail/images/top_settings_over.gif";
  img = new Image();
  img.src = "/webmail/images/top_logout_over.gif";
  img = new Image();
  img.src = "/webmail/images/top_find_over.gif";
}
function preloadLeftMenu() {
  var img = new Image();
  img.src = "/webmail/images/inbox_over.gif";
  img = new Image();
  img.src = "/webmail/images/create_mail_over.gif";
  img = new Image();
  img.src = "/webmail/images/address_book_over.gif";
  img = new Image();
  img.src = "/webmail/images/settings_over.gif";
  img = new Image();
  img.src = "/webmail/images/logout_over.gif";
}