function changeBG(){
	//alert("images/nrf_background"+val+".jpg");
	//document.body.background = "nrf_background"+val+".JPG";
	rand = Math.floor(Math.random()*2);
	//document.getElementById("mainBody").style.backgroundImage = "url('images/nrf_background"+rand+".jpg')";
	//alert("url('images/nrf_background"+rand+".jpg')");
	document.body.style.backgroundImage = "url('images/nrf_background"+rand+".jpg')";
}