This would not be hard to do. There are standard names for the auto complete form inputs. The browser (or plugin) could be configured to notify you if some/any

This would not be hard to do. There are standard names for the auto complete form inputs. The browser (or plugin) could be configured to notify you if some/any of those fields are about to be posted and warn the user using a native code generated pop-up (not a web pop-up).