How to decrypt encrypted data generated by the Crypthography component on a webpage?

Could you please expand on that? I am trying to encrypt my fields using AES-256 encryption along with a key. The test app to encrypt or decrypt works well with the builtin encryption module. I however need to encrypt the fields, upload it to firebase realtimedb then decrypt this encrypted data on a web page after pulling the encrypted data from the firebase realtime db.
Please advice on how this can be done using .js files (code)
Thanks in advance.