Configuring Firefox as the default Web browser

Download and extract the Firefox distribution somewhere like $HOME/ff3/firefox. Now we need to tell Debian where it is:

x61:~/ff3/firefox% sudo update-alternatives --install /usr/bin/x-www-browser x-www-browser ~/ff3/firefox/firefox 50

And now we need to set x-www-browser to our new configuration option.

x61:~/ff3/firefox% sudo update-alternatives --config x-www-browser

There are 2 alternatives which provide `x-www-browser'.

  Selection    Alternative
-----------------------------------------------
*+        1    /usr/bin/iceweasel
          2    /home/hendry/ff3/firefox/firefox

Press enter to keep the default[*], or type selection number: 2
Using '/home/hendry/ff3/firefox/firefox' to provide 'x-www-browser'.

Now run x-www-browser and happy browsing.