// JavaScript Document

if (document.getElementById) { window.onload = swap };
function swap() {
var numimages=18;
rndimg = new Array("images/head/head-image-1.jpg", "images/head/head-image-2.jpg", "images/head/head-image-3.jpg", "images/head/head-image-4.jpg", "images/head/head-image-5.jpg", "images/head/head-image-6.jpg", "images/head/head-image-7.jpg", "images/head/head-image-8.jpg", "images/head/head-image-9.jpg", "images/head/head-image-10.jpg", "images/head/head-image-11.jpg", "images/head/head-image-12.jpg", "images/head/head-image-13.jpg", "images/head/head-image-14.jpg", "images/head/head-image-15.jpg", "images/head/head-image-16.jpg", "images/head/head-image-17.jpg", "images/head/head-image-18.jpg"); 
x=(Math.floor(Math.random()*numimages));
randomimage=(rndimg[x]);
document.getElementById("header-image").style.backgroundImage = "url("+ randomimage +")"; 
}