var banner = new Array();

    banner[0]='https://i.servimg.com/u/f75/16/48/37/03/logonu11.jpg';
    banner[1]='https://i.servimg.com/u/f75/16/48/37/03/shana10.jpg';
    banner[2]='https://i.servimg.com/u/f75/16/48/37/03/molino10.jpg';
    banner[3]='https://i.servimg.com/u/f75/16/48/37/03/save10.jpg';





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