Script Automatische E-Mailadressen Entschlüsselung auf Webseite - Wie verschlüsseln?

/** 
 * @param encryptedMail 
 *        The encrypted mail link/address. 
 * @return 
 *        The decrypted mail link/address. 
 */ 
function decryptMail(encryptedMail) 
{ 
  var mail = '';   
  var mchar; 
   
  // The encrypted mail address is URI decoded 
  encryptedMail = decodeURIComponent(encryptedMail); 
  for (var i = 0; i < encryptedMail.length; i++) { 
    // Each character in the mail address is 
    // ...converted to its decimal ASCII code 
    mchar = encryptedMail.charCodeAt(i); 
    // ...XORed with a "magic number"  
    mchar ^= (31 - (i % 5)); 
    // ...converted to a character and appended to the final string 
    mchar = String.fromCharCode(mchar); 
    mail += mchar; 
  } 
   
  return mail; 
}

<span style="text-decoration: underline;"> </span><script language="JavaScript" type="text/javascript">if (window.decryptMail) {  document.write(decryptMail('da gehört die verschlüsselte emailadresse eingesetzt'));}document.write('<span style="display: none;">');</script>&lt;Diese E-Mail-Adresse ist gegen Spam Bots gesch&uuml;tzt, zum Ansehen m&uuml;ssen Sie in Ihrem Browser JavaScript aktivieren.&gt;<script language="JavaScript" type="text/javascript">document.write("</");document.write("span>");</script>