function click(evt) {

  var message = "Sorry, you don't have permission to right-click.";

  if (navigator.appName.indexOf("Microsoft") != -1){
    if (event.button==2) {
       return false
    };
   };

  if (navigator.appName.indexOf("Netscape") != -1) {
    if ( evt.which == 3 ) {
      return false
    };
  };
};

   if (navigator.appName.indexOf("Netscape") != -1) {
    document.captureEvents( Event.MOUSEDOWN )
  };

  document.onmousedown = click;