var banner = new Array();

banner[0]='https://i.servimg.com/u/f67/15/67/17/69/bannop10.jpg';
banner[1]='https://i.servimg.com/u/f69/15/99/92/88/bannop10.jpg';
banner[2]='https://i.servimg.com/u/f69/15/99/92/88/bannop11.jpg';

document.getElementById('i_logo').src= banner[Math.floor(Math.random()*banner.length)];