Disble right click in browser

<SCRIPT language=JavaScript1.1>
<!-- Begin
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("Sorry, you do not have permission to right click.");
return false;
}
else if (navigator.appName == 'Mozillz Firefox' && 
(event.button == 2 || event.button == 3)) {
alert("Sorry, you do not have permission to right click.");
return false;
}
else if ((event.button == 2 || event.button == 3)) {
alert("Sorry, you do not have permission to right click.");
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;
//  End -->
</SCRIPT>