Firefox 3 Site Specific Zoom

Martin Brinkmann
Feb 24, 2009
Updated • Dec 29, 2013

firefox site specific zoom level

The last article about Firefox's zoom capabilities received several interesting comments that discussed the zoom functionality of the browser.

What many users who commented did not know was that the zooming behavior changed in Firefox 3. It is still possible to zoom in or out of a website using keyboard shortcuts or the Firefox menu but observant visitors will notice that the zoom level seems to get saved on a per-domain basis.

This means that the actual zoom level will always be saved in Firefox 3 and therefor be displayed whenever the user visits a page on the domain.

In short: Firefox 3 will remember the current zoom level and display any page on the domain using it. This can lead to all kinds of troubles if a user does not know that Firefox 3 stores that setting.

While it is easy enough to restore the original zoom level, you may prefer to restore the old functionality instead. In older versions, the zoom level was not saved which meant that it was only active for as long as the website was open in Firefox. Once closed, the zoom level would automatically be reset to its default value.

There is however a new parameter in the Firefox configuration that can be changed to disable the automatic storage of zoom levels in Firefox 3.

Type [about:config] in the Firefox 3 location bar and filter for the following term: browser.zoom.siteSpecific. The default value for the parameter is true which means that the feature is enabled.

To disable it simply double-click the entry so that it changes to false. This has the effect that Firefox 3 and newer versions of the browser won't remember the zoom level and display all websites in default view on launch.

Just repeat the instructions to enable the feature again. You need to set the parameter to true in the configuration to do so.


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  1. Transcontinental said on February 24, 2009 at 5:21 pm

    Ya, NoSquint is the best way to handle zoom, even lets you choose – and remember if set to – between text and page zoom: perfect.

    Concerning browser.zoom.siteSpecific, my sick brains was imagining a user who cleaned all caches, everything… but had zoomed on THE page which got remembered with browser.zoom.siteSpecific … wow! That would be a good ‘Columbo’ scenario, no?!

  2. OpenZer0 said on February 24, 2009 at 12:48 pm
  3. lars said on February 24, 2009 at 11:10 am

    How do I enforce a standard zoom for all websites? Most of the sites have to small text on my TV when browsing on the HTPC, so its kinda annoying to zoom in on each new website.

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