There are also some fairly significant usability issues with autosubmit. As mentioned, it's pressing the enter key (regardless of how that's accomplished) and if the results of doing that were predictable for all forms, that would be great, but it's just not. The most common example of when autosubmit stinks is when you need to enter additional data 1Password is unable to fill. I've got an account that requires an additional PIN code entered with one of those obnoxious on-screen click keyboards, for example, and I had 1Password submit that Login without that PIN 2 or 3 times before I remembered to disable it for that site. Another I've seen are quasi-two-page forms, where the password field loads automatically after you enter your username. Depending on how fast that field loads, behavior can be totally different based on where focus is. I've had it reload the page, submit incomplete info, and do nothing at all. It also sometimes, though, rarely, lead to data loss when a password change was submitted prematurely when trying to fill an existing password.