HOWTO: Backspace in Firefox 2

In default, Firefox's backspace don't work as Return to the last page(Ubuntu).
So, here it is the solution:

1. Type about:config in the address bar, and press enter.
2. Type browser.backspace_action in the filter bar. One result should come up.
3. Double click it and change the value to zero.
4. Close the configuration window, and enjoy!