// This script hereby is dedicated in the Public Domain
// as long as nobody else claims the copyright for it.
// origin: 2000-01-08 nospam@geht.net http://tools.geht.net/rot13.html
// Use at own risk.
var last="";
var rot13map;

// The problem is that JavaScript 1.0
// does not provide a Char to Numeric value conversion
// Thus we define a map.
// Because there are 64K UniCode characters, this map does not cover all characters.
function rot13init()
{
  var map = new Array();
  var s   = "abcdefghijklmnopqrstuvwxyz";
  
  for (i=0; i<s.length; i++)
    map[s.charAt(i)]			= s.charAt((i+13)%26);
  for (i=0; i<s.length; i++)
    map[s.charAt(i).toUpperCase()]	= s.charAt((i+13)%26).toUpperCase();
  return map;
}

function rot13(a)
{
  if (!rot13map)
    rot13map=rot13init();
  s = "";
  for (i=0; i<a.length; i++)
    {
      var b = a.charAt(i);

      if (b=='@')
	{
		s += '~';
	}
      else if(b=='~')
	{
		s += '@';
	}
      else
	{
		s	+= (b>='A' && b<='Z' || b>='a' && b<='z' ? rot13map[b] : b);
	}
    }
  return s;
}

function upd()
{
  if (document.forms[0].text.value==last)
    return;

  last = document.forms[0].text.value;
  document.forms[0].rot13.value = rot13(last);
}