serialization (save and load game) on a javascript based project, should i/can i use c#, or should stick with javascript?

basically i have a javascript based project and im trying to find a serialization script for saving and loading, the only scripts i can find are c#, can i use c# script with lots of javascript, and should i?

Honestly you should just leave JavaScript, C# can do some things that JavaScript can’t, and there is way more documentation for C# (because the JavaScript used in Unity is not really JavaScript, but a Unity derivative of it) and if you were ever to collaborate with someone, C# will be better.

As for mixed languages in a game, as long as they are not the same script file, it will be OK.