if (document.getElementById) { window.onload = swap };
function swap() {
var numimages=9;
rndimg = new Array("/danceonthebox/images/bigbg/9.jpg", "/danceonthebox/images/bigbg/8.jpg", "/danceonthebox/images/bigbg/7.jpg", "/danceonthebox/images/bigbg/6.jpg", "/danceonthebox/images/bigbg/5.jpg", "/danceonthebox/images/bigbg/4.jpg", "/danceonthebox/images/bigbg/3.jpg", "/danceonthebox/images/bigbg/2.jpg", "/danceonthebox/images/bigbg/1.jpg"); 
x=(Math.floor(Math.random()*numimages));
randomimage=(rndimg[x]);
document.getElementById("mainWrapper").style.backgroundImage = "url("+ randomimage +")"; 
}