Colt blogs about Obfuscating Web Pages using a commercial product.
The fact is, because the script is interpreted at runtime, the scripting engine has to be able to decode the encrpyted data and needs information on how to do this. With the way the HTTP protocol works and current scripting technologies, if the scripting engine can get this information, so can the hacker. Even the Microsoft ScriptEncoder for encrypting VBScript has been broken.
Only server side code can be protected (BTW, have you locked down your webserver using IPSEC? If not, you should consider doing so!)