We coincidentally had this same question about this same article today. I'll be working with our developers to see if we can get this to work and I'll report back to this thread.
CC Justin Norris
Sounds like this hasn't been natively integrated yet.
Question: if i embed my form on a Marketo page, can I just use something like this to append it?
var email = document.getElementById("Email");
email.setAttribute("autocomplete","email");
Sure, doesn't matter if it's on a Marketo LP or not. Put it in MktoForms2.whenReady. I demoed this in a Community post at some point.