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Modify pref.js with script not working

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  • Last reply by cor-el

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I am trying to modify the pref.js file, specifically to enforce using the "Use system proxy settings" in the Connection Settings section of Options. I am able to modify it via a VB Script (changing user_pref("network.proxy.type", 2); to a '5') , but when I start Firefox, then go into Options, it is still set for "Automatic proxy configuration URL (whic is blank and we do not use).

My questions is how can I change the user preferences to always be set to Use system proxy settings via a script and have it stay. Very frustrating....

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hi DaGbyte, please refer to http://kb.mozillazine.org/Locking_preferences - this will be a far better method than fiddling with the live preferences file...

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You can use a mozilla.cfg file in the Firefox program folder to lock prefs or specify new (default) values.

Place a local-settings.js file in the defaults\pref folder where also the channel-prefs.js file is located to specify using mozilla.cfg.

pref("general.config.filename", "mozilla.cfg");
pref("general.config.obscure_value", 0);

These functions can be used in the mozilla.cfg file:

defaultPref();	// set new default value
pref();		// set pref, allow changes in current session
lockPref();	// lock pref, disallow changes
  • The mozilla.cfg file needs to be in the main Firefox program folder.
  • The local-settings.js file is located in the defaults\pref folder.
  • The mozilla.cfg file needs to start with a comment line (//) because this first line is skipped (ignored).

See: