var banner = new Array();

banner[0]='https://i.servimg.com/u/f43/16/83/67/92/outlan10.jpg;
banner[1]='http://img14.imageshack.us/img14/7254/outlands.png';
banner[2]='https://i.imgur.com/dJXY50y.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)];",3000);