var alertmessage = "© 2000-2001 Virtual Tour 360\n\nIt's just like being there!";
function rtclickcheck(keyp){
  if (navigator.appName == "Netscape" && keyp.which == 3) {
    alert(alertmessage);
    return false;
  }
  if (navigator.appVersion.indexOf("MSIE") != -1 && event.button == 2) {
    alert(alertmessage);
    return false;
  }
}
document.onmousedown = rtclickcheck