var offset = 7;

function encode(str)
{
 var encoded = "";

 for (var i = 0; i < str.length; i++)
 {
   var c = str.charCodeAt(i) + offset;
   encoded += c ;
   if (i < str.length - 1) encoded += ",";
 }

 document.write(encoded); 
}

function decode()
{
  var str = "";

  for (var i = 1; i < arguments.length; i++)
  {
    var p = arguments[i] - offset;
    str += String.fromCharCode(p)
  }

  document.getElementById(arguments[0]).innerHTML = str.link("mailto:" + str); 
}