Is it possible to set config settings on Firefox from a Addon

Question

I'm looking for a way to print from web without prompting the print dialog (I just made the question).

I found This method for Firefox and it seems to work, but it obviously will affect all websites. So I'm thinking of developing a Firefox Addon that makes this configuration to affect only specific websites.

I don't know nothing about building Firefox addons, but if it's possible to change settings this way I will learn how to do it.

So my question is.. Is it possible to set config settings on Firefox from a Addon and for specific websites?

Thanks a lot.

Answer 1

If you are going to develop a Firefox addon you could "easily" replace the print button and delegate to the standard print action on normal websites. For a list of URLs, i.e. your web site, you temporarily set print.always_print_silent to true and be done with it.

For modifying a preference in an addon you would something like this:

// Get the "accessibility." branch
var prefs = Components.classes["@mozilla.org/preferences-service;1"]
    .getService(Components.interfaces.nsIPrefService).getBranch("accessibility.");

// prefs is an nsIPrefBranch.
// Look in the above section for examples of getting one.
var value = prefs.getBoolPref("typeaheadfind"); 

// get a pref (accessibility.typeaheadfind)
prefs.setBoolPref("typeaheadfind", !value); // set a pref (accessibility.typeaheadfind)

(taken from this snippet).