Javascript Text Encoding/encrypting

MS has published on its sites javascript encoder, which enables "encrypting"
javascript code. It allows hiding js code from being seen as a text file.
There is a decoder for it, available in the net, freeware, srcdec14.exe.

I have tested both, encrypting, decrypting, the source and the final files
are identical.

But what I met on a certain site is a js file, encoded I think in another
way, because I cannot decrypt it using the srcdec14.exe.

This is why I have a question for genarally any information cons. this
subject (are there several ways MS is able to read encrypted js files?, do
you know other decoders?,...)