var banner = new Array();

banner[0]='https://i1192.photobucket.com/albums/aa323/kaisergacu/logotipos%20rotativos/01.jpg';
banner[1]='https://i1192.photobucket.com/albums/aa323/kaisergacu/logotipos%20rotativos/02.jpg';
banner[2]='https://i1192.photobucket.com/albums/aa323/kaisergacu/logotipos%20rotativos/cabezera.jpg';

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

setInterval("document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];",9000);