In Firefox, you can set your backspace to better use by getting it to either go back to the previous page or act as page up function.
Even if monitored, a casual attacker will be stymied by the presence of backspace and other characters that apparently alter the presence or order of characters in the password string.
Match a backspace if in character matching mode.
You could also see it as a trap for users because they can move the cursor and inadvertently backspace away characters that were not the last ones keyed in.
Delete - backspace and erase one character or number entry
If you make a mistake, you can use the usual keyboard shortcuts -- ctrl+z will undo your previous action while the backspace key will remove the element from the page.
By default you can use the cursor keys, and backspace, to move around and edit the input line, just like with the Bash shell.
Slip up on the backspace key to delete all chars in buffer.
ASCII characters to indicate carriage return or tab or backspace; typed by depressing a key and the control key at the same time.
hit the backspace key on a computer or typewriter keyboard.
I wish my mouth had a backspace key.