I would very much like there to be a WEB standard for this, but unfortunately there is not!
I studied this for several days and gathered a lot of information and I will share it with you.
Before developing or using an internet hack you need to know that there are 2 types of Autocomplete. There is the autocomplete of the page and the autocomplete of the browser.
This is the global browser autocomplete. It appears whenever you define autocomplete="off"
or when you define no autocomplete but define type="email"
for example. The global autocomplete suggests emails you've used on other sites. The global autocomplete has a manage button at the bottom and can be disabled in the browser config.