function changeBGImg(){
var randomImg = new Array(); 
randomImg[0]="http://lib.store.yahoo.net/lib/yhst-42522233509519/body-bg.gif";
randomImg[1]="http://lib.store.yahoo.net/lib/yhst-42522233509519/body-bg1.gif";
randomImg[2]="http://lib.store.yahoo.net/lib/yhst-42522233509519/body-bg2.gif";

randomNumber = Math.floor(Math.random()*randomImg.length);
document.body.background=randomImg[randomNumber];
}