prueba con este:
<script language=JavaScript>
<!--
//Disable right click script III- By Renigade (
[email protected])
//For full source code, visit
http://www.dynamicdrive.com
var message="";
///////////////////////////////////
function clickIE() {if (document.all) {(message);return false;}}
function clickNS(e) {if
(document.layers||(document.getElementById&&!docum ent.all)) {
if (e.which==2||e.which==3) {(message);return false;}}}
if (document.layers)
{document.captureEvents(Event.MOUSEDOWN);document. onmousedown=clickNS;}
else{document.onmouseup=clickNS;document.oncontext menu=clickIE;}
document.oncontextmenu=new Function("return false")
// -->
</script>