var am = "Opcja niedostępna";
var bV = parseInt(navigator.appVersion);
var bNS = navigator.appName=="Netscape";
var bIE = navigator.appName=="Microsoft Internet Explorer";

function nrc(e) {
	if (bNS && e.which == 3){
	alert(am)
	return false;
	} else if (bIE && (event.button == 2)) {
	alert(am)
	return false;
	}
}
document.onmousedown = nrc;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (bNS && bV<5) window.onmousedown = nrc;