Apps similar to Jscrambler include DomainLockJS, which is free and open source. Other options are JavaScript Obfuscator. Between them they cover the web.
DomainLockJS is a free code generator to protect your Javascript files by locking them to your domain. Prevent unauthorized use of your scripts and prevent them from running on unauthorized websites.
This webapp can obfuscate your JavaScript with various levels of protection, including: self-defending code, domain lock and debug protection. It's based on a open source (Node.js) project, so you can run on your own server if you like.
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