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I am editing a lot of data in a web application using Firefox, and occasionally I hit the backspace key without focusing on a field, and FireFox goes back one page, erasing all the data I entered.

The developers of the application say that a box should come up asking me if I am sure I want to leave the page, because I have unsaved changes. That only works sometimes. Until they fix that behavior, what can I do on my local machine to disable the backspace button's "go back" functionality?

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up vote 11 down vote accepted
  • Navigate to about:config in the address bar
  • set the filter to browser.backspace_action

It is an integer value, change it to the desired setting:

0 - Pressing Backspace will go back 1 page in session history and Shift + Backspace will navigate forward 1 page in session history.

1 - Pressing Backspace will scroll the page up in the current document and Shift + Backspace will scroll it down.

Any other positive integer (2 or more) will unmap the backspace key, which is what you want. But keep in mind, the integer data type has a limit, so don't got crazy. 2 will be fine.

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Awesome, thanks! – Josh Oct 28 '09 at 19:45
You're welcome! just keep in mind integers have a limit, so I'd just set it to 2 :) – John T Oct 28 '09 at 19:47
That's very interesting. What are some other useful configurations you can with that way? Is there a list out there on the interwebs? – wahle509 Oct 28 '09 at 19:48
@wahle509 take a look at this other Superuser question - "What do you think is the most useful about:config setting in Firefox?" The best (useful) ones can be found in there. Link:… – John T Oct 28 '09 at 20:00
  • Type about:config into your firefox browser
  • type in "backspace" in filter
  • double click "browser.backspace_action" change the value 0 to 2.
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The keyconfig add-on works for me (though the Browser.backspace_action preference might be sufficient for you).

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Thanks -- this is a good easy alternative to about:config; – Josh Oct 28 '09 at 23:11

The DisableBackspaceNavigation addon works as advertised:

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Thanks -- this is a good easy alternative to about:config; – Josh Oct 28 '09 at 23:09

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