if (document.images) {
port3a = new Image;
port3b = new Image;
port3c = new Image;
port3a.src = 'images/port3_a.jpg';
port3b.src = 'images/port3_b.jpg';
port3c.src = 'images/port3_c.jpg';
} else {
port3a = '';
port3b = '';
port3c = '';
document.rollimg = '';
}