sevenkader on "I want to decode & back to normal text"

Every theme I change to my "&"s are always &amp, I'd love to get rid of that.

I've looked around and found this

var decoded = encoded.replace(/&/g, '&');

I don't know if that would do the trick, but I also don't know where I should be placing it. May anyone let me know where? Or, if there's a better option, may you let me know? Thank You!!