How can I prevent javascript code theft?

Question

Actually I'm developing a Chrome extension and a jQuery plugin to upload it and sell it on Codecanyon. When I "Inspect source" of the page and I click on the "Resources" tab, the javascript file looks empty. How does Codecanyon do that? I want to have file theft prevention in my own website too, but I don't know how to do it. I know php and javascript and there's no method to do it, because the browser downloads the file to execute it.

You can see the example here.

Answer 1

If you see it's empty, it means that it's empty. There is no way to hide your javascript code from a client that must execute the code.

Answer 2

You cannot hide it because your browser needs it to perform it. Simple as that.

You need to understand that it is a script executed on the client side. It is not compiled (meaning it's not a binary (0 and 1 machine language)). So it is freely readable.

Nevertheless you can obfuscate it using tools like YUI compressor

Basically this kind of tools remove extra spacing, tabs line returns and rename methods (like method "a" standing for "MyShinyMethodWhoMakesNiceStuff") and variables. That makes it very difficult to read and understand code. Reverse engineering is thus harder to achieve.

Some uses some tricks like base64 or other encode and decode part of code with a function but it's only tricks and will not fool the sharp eye.

By obfuscation, you make people spend much more time in analyzing your code and stealing is thus much more complex, and takes time. Let's say you made a nice javascript plugin that makes every white background in purple (ok, not so great example but used it just for having an imaged example). Somebody might want to steal it and makes it blue instead of purple. If code is obfuscated, he might think that's easier to copy your idea and rewrites it on his own with his own code and blue background, it will takes him less time than reverse engineers and understanding wells yours, easier to maintain in the time too. In the end he will "only" "steal" your idea but not your code.

I think that in the end, it's just a matter of time.