Hey dear, if you want know more about Hide external application so, you can check this link below: forums.devx.com/showthread.php?178831-Hide-external-application Please keep improved your self.
You can't hide HTML and CSS. You can obfuscate Javascript (there are programs that will do that), but obfuscated Javascript is pretty easy to unobfuscate. You don't have to 'hide' server-side code (like PHP) because the user never sees it.
You didnt mention the language and the programming platform you want to hide your source code in. Is it server side or in any other application you have developed or what?