var banner = new Array();

banner.push('adresse_image_1');
banner.push('adresse_image_2');
banner.push('adresse_image_3');

document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];
banner.push('https://i.servimg.com/u/f21/15/81/51/04/dscn0910.jpg');