The following is an example of the simple 'alphabet code.' Each letter in your word is offset by 1 letter, so that 'A' becomes 'B' and 'B' becomes 'C' etc.
<HTML>
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
<!-- Beginning of JavaScript -
function encode(text) {
Ref = "0123456789abcdefghijklmnopqrstuvwxyz.-~ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Result = ""
for (Count = 0; Count < text.length; Count++) {
Char = text.substring(Count, Count + 1);
Num = Ref.indexOf(Char);
EncodeChar = Ref.substring(Num + 1, Num + 2)
Result += EncodeChar
}
document.form1.result.value = Result
}
// - End of JavaScript - -->
</SCRIPT>
</HEAD>
<BODY bgcolor="beige">
<FORM name="form1">
<table border=0>
<tr>
<td>
Type your word
<td>
<INPUT NAME="input" TYPE=Text>
<br>
<td>
<INPUT TYPE=Button VALUE="submit" onClick="encode(this.form.input.value)">
<tr>
<td>
Result:
<td>
<INPUT NAME="result" TYPE=Text>
</table>
</FORM>
</BODY>
</HTML>