var banner = new Array();

banner[0]='https://i329.photobucket.com/albums/l400/dany098/Banner-1.png';
banner[1]='https://i862.photobucket.com/albums/ab188/Daniel-SamaOtaku/digimonforosito2.png';

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