Key binding in Battlefield gamesEdit
With the Battlelog system in place, the player cannot currently change controls unless they are in an active server.
Functions are now limited to one key, one mouse control, and/or one joystick/gamepad control. (Players who have installed third-party input software may be able to sidestep this constraint.)
However, a single input can be mapped to multiple functions. For example, the Sprint and Scope stabilization (hold breath) functions are both mapped to a PC player's Shift key. Certain abilities (e.g. crouching) have alternative inputs such as single-press, combo with a similar function (press for one function, hold for a second function), or toggled control.
Default Keyboard Layout
Follow http://battlefield.wikia.com/wiki/File:BF3-KeyLayouty.png and click on image for better size/quality.