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https://support.mozilla.org/en-US/questions/962990 followed the about:cofig advise and now no matter what everything is so small I cant pg. it! Help!!I

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Since I upgraded firefox my resolution is too big to even get Facebook full pg or play some of my games, the whole screen does not fit. So I followed the advise https://support.mozilla.org/en-US/questions/962990. Now I can't even see my page everything is so small. I have tried restore, re-install, nothing works. HELP

Since I upgraded firefox my resolution is too big to even get Facebook full pg or play some of my games, the whole screen does not fit. So I followed the advise https://support.mozilla.org/en-US/questions/962990. Now I can't even see my page everything is so small. I have tried restore, re-install, nothing works. HELP

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Hit Windows button and R, type in C:\Users\put your name here\Appdata\Roaming\Mozilla\Firefox\ open the next folder and delete prefs.js file.

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You can edit the prefs.js file in the Firefox profile folder with a plain text editor like Notepad and remove the line with the layout.css.devPixelsPerPx pref or change the value to 1.0

  • user_pref("layout.css.devPixelsPerPx", "1.0");
  • C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

The "Application Data" folder in XP/Win2K and the "AppData" folder in Windows Vista and Windows 7 and later versions are hidden folders.

Alternatively you can create a file user.js and place the above posted user_pref() line in the user.js file and start Firefox once to reset the pref.

After having done this and have restarted and closed Firefox you can remove the user.js file because otherwise you can't make changes to this pref that will last.


Be careful and do not set the layout.css.devPixelsPerPx to a value that is too small.

You can set the layout.css.devPixelsPerPx pref to 1.0 (current default value is -1) to restore the behavior of previous Firefox versions.
If you want to make changes then start with this 1.0 value and increase or decrease its value in 0.1 or 0.05 steps.

If you want or need to make further changes then start with a value of 1.0 and adjust this value with 0.1 steps or 0.05 for finer adjustments.

  • Use values between 1.0 and about 0.5 to reduce elements in size (do NOT go all the way to 0.05!)
  • Use values greater than 1.0 to magnify and make elements larger (percentage divided by DPI, % / DPI).

If web pages needs to be adjusted after changing this pref then you can look at the Default FullZoom Level or NoSquint extension.

Use this extension to adjust the font size for the user interface: