Block the 'Delete goes back' action in Firefox
QUOTED FROM: http://www.macosxhints.com/article.php?story=20070511123925218
Mon, May 14 2007 at 7:30AM PDT • Submitted by cdimara
Though opinions seem to vary, I'm squarely in the "annoyed by the backspace in Firefox" camp. By default, the backspace key triggers a 'Back' action, sending you to the previous page in your history. You'd need an Xserve to count the email, messages, and form values that I've lost to this redundant, misappropriated shortcut. Fortunately, the solution can be found in the Firefox's about:config Browser.backspace_action preference.
How to block the backspace action:
1. Open a new Firefox window
2. Enter about:config into the location bar. Press Enter. The about:config page will open. It's a huge list of Firefox configuration properties.
3. Enter browser.backspace into the filter. This will bring the 'Browser.backspace_action' preference into view.
4. Contrl-click the 'Browser.backspace_action' Value column, and choose Modify from the pop-up menu, then enter a new value of 2.
5. Press OK.
That's it! You're done! Fear the backspace key no longer! Of course, you can still use Command-] and Command-[ to go Back and Forward. If you ever want to restore the backspace action, simply change the value of the 'Browser.backspace_action' preference back to 0, using the above process.