When I am on Firefox, I would like the space bar to scroll not the whole page but only half of it in order not to lose focus when I read.

I suppose there must be an easy workaround by changing a value in about:config but I can't find it. Or maybe with some Greasemonkey custom script, but I am kind of a noob.

There is also the "Scroll Half Page" extension on the Chrome Web store, could that be easily adapted?

I am on Linux Mint 19.1 with the latest version of Firefox.

  • I'd like this too. Oct 27, 2019 at 1:47
  • My solution was too learn to use the vimium firefox add-on since I am a vim user. Then you can set some shortcuts for scrolling half a page. I chose 'u' and 'm'.
    – cassepipe
    Oct 27, 2019 at 17:20
  • If that solution works for you, you're welcome to answer your own question and mark it as accepted the next day. Oct 27, 2019 at 20:52
  • I would rather not since it seems to be more of a workaround that vim users might be interested in but I am still expecting a solution that targets the average reader, someone eager for a new tweak but not to change wholly his probably already overtweaked superuser browsing habits. Don't you agree ?
    – cassepipe
    Oct 28, 2019 at 13:01
  • I believe the general rule is, if it works for you, then it's an acceptable answer. At the very least, it's a valid answer! It's up to you. Oct 28, 2019 at 13:04

2 Answers 2


The solution I found that works for me is to get the Vimium firefox extension and then to insert map <space> scrollPageDown in the Custom key mappings text box in the Options.

It will only scroll half the page.

If you happen not to be a Vim user (it's an old and widespread powerful modal text editor that runs in the terminal), you may want to disable all of Vimium keymappings by placing unmapAll just above the map <space> scrollPageDown line.

  • Please don't forget to check back in 48 hours to accept your solution so it can be found in the future. From Review Oct 5, 2021 at 10:59

The Scrollkey extension worked for me:


You can customize the amount of scrolling (in pixels), enable shortcuts for horizontal scrolling and even use Page Up and Page Down if you don't care about vim-like scrolling with J and K.

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