function right(e) {
    if (navigator.appName == 'Netscape' && (e.which == 3 || e.which == 2)) return false;
    else if (navigator.appName == 'Microsoft Internet Explorer' && (event.button == 2 || event.button == 3)) {
        alert("Copyright Shirts & co");
        return false;
    }
    return true;
}

document.onmousedown = right;
document.onmouseup = right;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (document.layers) window.captureEvents(Event.MOUSEUP);
window.onmousedown = right;
window.onmouseup = right;