codice:
function radioChecked() {
	for (var aPayments = document.pagamento.accredito, nLen = aPayments.length, nIdx = 0; nIdx < nLen; nIdx++) {
		if (aPayments[nIdx].checked) {
			document.pagamento.action = aPayments[nIdx].value === "bonifico" ? "checkout.asp" : "paypal.asp";
			document.pagamento.submit();
			return;
		}
	}

alert("fare una scelta!"); 
}
https://developer.mozilla.org/en-US/...ents/if...else