var msg = "Sorry, that action is not allowed. If you want to use anything on this site, please ask permission.";
var bV  = parseInt(navigator.appVersion)
var bNS = navigator.appName=="Netscape"
var bIE = navigator.appName=="Microsoft Internet Explorer"

function nrc(e) {
   if (bNS && e.which > 1){
      alert(msg)
      return false
   } else if (bIE && (event.button >1)) {
     alert(msg)
     return false;
   }
}

document.onmousedown = nrc;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (bNS && bV<5) window.onmousedown = nrc;