//  ---------------------------------------------------------------------------
function errorBox (message, url, line) {
  traceln ('###  oops...'); 
  traceln ('A JavaScript-error occured!'); 
  traceln ('error message: '+message); 
  traceln ('document: '+url); 
  traceln ('line no.: '+line); 
  traceln ('browser version: '+navigator.userAgent); 
  traceln ('please inform mail@horst-walther.de');
  return true;
}

//  ---------------------------------------------------------------------------
self.onerror = errorBox;