var eventCounter = 0;
var maxEvents = 1; // set this to be the max number of normal alert messages.
var msg = "MSDS Europe - Your MSDS Expert";
if(document.layers) window.captureEvents(Event.MOUSEDOWN);

function no_click(e){
if (navigator.appName == 'Netscape' && ( e.which == 2 || e.which == 3))
 {
   if (++eventCounter >= maxEvents)
     alert(msg);
   else
     alert(msg);
   return false; // this works!
 }
 if (navigator.appName == 'Microsoft Internet Explorer' && (event.button == 2 || event.button == 3))
 {
   if (++eventCounter >= maxEvents)
     alert(msg);
   else
     alert(msg);
   event.returnValue=false; // this does not really work... (it should - bug in IE?)
   return false; // this is just here for show - it does nothing in IE.
 }
}
window.onmousedown=no_click;
document.onmousedown=no_click;