why does FIREFOX bring up the ready access to my on-line bank account with user name and passcode already filled in

when I try to access my on line bank account, I select MOZILLA icon from my desktop, Then I type in the bank name\It brings me to a list which I choose the BANK ON-LINE BANKING SELECTIO this immediately brings me to a LOGIN selection which I click and it displays my LOG with user name and PASSWORD already filled in such that clicking LOG takes me immediately to my on-line banking program without user name and password entry ever being required from the user. This access is mode is totally unacceptible to me