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.