Bloquer Ctrl+c

Codigo
<SCRIPT LANGUAGE="JavaScript1.2">
function alerta(){
    alert('nada de ctrl:C');
    return false;
}

function rejeitaTecla(oEvent){
    var oEvent = oEvent ? oEvent : window.event;
    var tecla = (oEvent.keyCode) ? oEvent.keyCode : oEvent.which;
    if(tecla == 17 || tecla == 44|| tecla == 106){
        alerta();
     }
}
</SCRIPT>


<SCRIPT LANGUAGE="JavaScript1.2">
document.onkeypress = rejeitaTecla;
document.onkeydown = rejeitaTecla;
document.oncontextmenu = alerta;
</script>

Video Aula