function zmenaon(radio){
	var loi = document.getElementById(radio);
	loi.style.background='url(img/sipka2.jpg) no-repeat center top';
	loi.style.cursor='pointer';
	}
	
	function zmenaoff(radio){
	var loi = document.getElementById(radio);
	loi.style.background='url(img/sipka.jpg) no-repeat center top';
	loi.style.cursor='pointer';
	}