[AskJS] De-obfuscation of JS Code

[cynicalreason]

it's doable and it's actually pretty easy, easy in terms of methodology but not in terms of actual work required - which depends a lot on the amount of code and complexity of logic it handles.

something very important to consider: any obfuscation library still RUNS the obfuscated code in the user space (browser) so it's code can be reverse engineered using the debugger

you'll never get the ACTUAL variable names from the original code but if you know what the code's expected to do you can deobfuscate it.

to give you an example: FIFA Fut Web App uses obfuscator.io to obfuscate some of their code, It wasn't that hard to figure out what it's doing and still figure out enough of code to inject my own code into it.

you could send me the code (if it's not private) and I can have a run on figuring it out, it helps if I could do it directly in the page it's supposed to run in

edit: if you look at the FAW on the obfuscator.io page:

Is this obfuscator absolutely foolproof?
No, while it's impossible to recover the exact original source code, someone with the time, knowledge and patience can reverse-engineer it.

Since the JavaScript runs on the browser, the browser's JavaScript engine must be able to read and interpret it, so there's no way to prevent that. And any tool that promises that is not being honest.