var banners = new Array(3);
var index;
		
banners[0] = "images/girl-banner-1.jpg";
banners[1] = "images/girl-banner-2.jpg";
banners[2]  = "images/girl-banner-3.jpg";
		
index = Math.floor(Math.random() * banners.length);
		
document.getElementById('banner').style.backgroundImage = 'url("' +  banners[index] + '")';