if(document.images) {
  var menu_off_home      = new Image;
  var menu_off_vision    = new Image;
  var menu_off_products  = new Image;
  var menu_off_mechanics = new Image;
  var menu_off_function  = new Image;
  var menu_off_faq       = new Image;
  var menu_off_how_to    = new Image;

  var menu_on_home      = new Image;
  var menu_on_vision    = new Image;
  var menu_on_products  = new Image;
  var menu_on_mechanics = new Image;
  var menu_on_function  = new Image;
  var menu_on_faq       = new Image;
  var menu_on_how_to    = new Image;

  menu_off_home.src      = 'img/menu_off_home.gif';
  menu_off_vision.src    = 'img/menu_off_vision.gif';
  menu_off_products.src  = 'img/menu_off_products.gif';
  menu_off_mechanics.src = 'img/menu_off_mechanics.gif';
  menu_off_function.src  = 'img/menu_off_function.gif';
  menu_off_faq.src       = 'img/menu_off_faq.gif';
  menu_off_how_to.src    = 'img/menu_off_how_to.gif';

  menu_on_home.src      = 'img/menu_on_home.gif';
  menu_on_vision.src    = 'img/menu_on_vision.gif';
  menu_on_products.src  = 'img/menu_on_products.gif';
  menu_on_mechanics.src = 'img/menu_on_mechanics.gif';
  menu_on_function.src  = 'img/menu_on_function.gif';
  menu_on_faq.src       = 'img/menu_on_faq.gif';
  menu_on_how_to.src    = 'img/menu_on_how_to.gif';
}