var banner = new Array();

banner[0]='https://i673.photobucket.com/albums/vv98/Ryoko30/logofcopia.png';
banner[1]='http://uppix.com/f-Daybreakers4fb808c10010048f.jpg';
banner[2]='http://uppix.com/f-1267797820_Daybr4fb8097e00100492.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)];",1000);