Disable right click without alert message 

<script language=JavaScript>
<!--


//Disable right click script III- By Renigade (renigade@mediaone.net)
//For full source code, visit http://www.dauspozi.com


var message="";
///////////////////////////////////
function clickIE() {if (document.all) {(message);return false;}}
function clickNS(e) {if
(document.layers||(document.getElementById&&!document.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.oncontextmenu=clickIE;}


document.oncontextmenu=new Function("return false")
// -->
</script>