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){

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

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