var backgroundImages=new Array(5);
backgroundImages[0]="../images/900image1.jpg";
backgroundImages[1]="../images/900image2.jpg";
backgroundImages[2]="../images/900image3.jpg";
backgroundImages[3]="../images/900image4.jpg";
backgroundImages[4]="../images/900image5.jpg";

onload=function(){
var e=(document.getElementById)?document.getElementById("myTableId"):(document.all)?document.all.myTableId:(document.layers)?document.myTableId:null;
if(!e)return true;
e.style.backgroundImage="url("+backgroundImages[Math.floor(Math.random()*backgroundImages.length)]+")";
}