// JScript File
var arr = new Array("images/altosax.gif","images/baritone.gif","images/bass.gif","images/bassoon.gif","images/cello.gif","images/clarinet.gif","images/flute.gif","images/horn.gif","images/oboe.gif","images/trombone.gif","images/trumpet.gif","images/violin.gif");

var increment = Math.floor(Math.random() * arr.length);

//pre-load image
var img = new Image();
img.src=arr[increment];

window.onload=function(){
document.getElementById('main_table').style.background="#f8f8f8 url("+img.src+") no-repeat fixed right bottom"
}