Developer method to disable Safari Credentials Manager on forms

I'm revisiting code I developed a while back for managing data entry about users, which includes giving them a username and password in the form that an administrator uses. I thought I'd found a way previous to get Safari to NOT try to over-write a field called username with the administrator's username and to NOT store the password they'd entered / reset against their credentials stored in the administrator's keychain. It seems to still be working in other browsers, but for Safari, it's stubbornly popping up "save this password" and offering to autofill... it's driving me nuts.

Is there a solution?

Developer method to disable Safari Credentials Manager on forms
 
 
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