How to prevent your JavaScript code from being stolen, copied, and viewed? [closed]

Question

I know its impossible for 100% protection, but something high or that works for majority of the users.

For instance, I encountered a site where viewing the current page's source returned nothing.

In another case, accessing or trying to download the .js files itself from browser

http://gget.com/somesecret.js,

would redirect you and stuff.

If you obfuscate your code, will it be very very difficult to decode it? if so that is also another good solution (what software is recommended) ?

Answer 1

It's simply not possible.

For a visitor's browser to be able to execute the script, they have to be able to download it. Not matter what trickery you try to pull with JS, server permissions etc., at the end of the day they can always just wget http://example.com/yourcoolscript.js. And even if they can't (e.g. you require "secret" headers for that request) that would likely inhibit the behaviour of most browsers, while not stopping a determined person from looking anyway.

Fundamentally, because JS is executed client-side, the client must have access to the "original" JS file.

One minor thing you can do is obfuscation, which can help a little bit. But since JS is interpreted, it's also its own deobfuscator - see one of my earlier answers for an example.

Basically - "if you build it, they will look". :-)