Click on the down-arrow next to the yellow helmet icon in the addon bar (top-right of the window) to change the User Agent for the current domain. Notes: the add-on bar may not be displayed by default. In this case, right click on the Firefox menu and select «Add-on bar». If you install it on Firefox 29, the icon will not appear by default, you will have to manually add it (I may fix it if I have some time).

Click on the helmet icon to quickly enable/disable this add-on.

If the page performs requests on other domains, the default UA will be used until a UA is explicitly specified for each domain.
Restarting the browser is not required.
Remember that any request will pass though the extension, which should slow down a little bit the browsing. In the configuration window, you can disable the replacement so you use it only when you really need it.

Warning: in several cases (including when Firefox crashes), your settings may be lost (because of a Firefox bug). I will work on a work-around when I have time.

A complete list of UA is available on this page.

If you need to change the UA at the javascript level, you can use a nice addon called User-Agent JS Fixer.

Known issues and possible improvements:
  • The UA is only changed in the request HTTP header, so it does not prevent Javascript to determine the real UA

  • Contact: «fabsk at free dot fr»

    Note: In the past, there was a native way to do that in Firefox, through the setting «general.useragent.override». Firefox does not support it anymore.

    Download files:


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