Scroll down half the screen size in Firefox

Question

Is it possible to have the spacebar not scroll down the entire page in Firefox? Scrolling one line at a time (with the down arrow) is very slow, but scrolling the entire screen (with spacebar) sets me off and I loose focus.

Is there a way to make the spacebar scroll the page the equivalent of approximately half the screen?

Just to be clear. When pressing spacebar, instead of the line in the bottom of the screen bring brought to the top, the line in the bottom should be brought to the middle.

Answer 1

Should be quite simple to accomplish in AutoHotkey. Download autohotkey, and use the following script with it. The script detects if you are in a input box.

#NoEnv  
SendMode Input
SetWorkingDir %A_ScriptDir% 
#IfWinActive, ahk_class MozillaWindowClass
{
    Space::
    If A_Cursor != IBeam
    {   
        Send {WheelDown 150}
    }else {
        Send {Space}
    }
    return
}             

Then adjust the amount of scrollsteps you want to scroll at {WheelDown 150} You can easily compile the script to an exefile if you want by using the Compiler that is included when you download autohotkey.

OR download this precompiled binary... http://www.megaupload.com/?d=D58JPT4U

Answer 2

It's just an undeveloped idea, but maybe somebody will make it real: A custom greasemonkey script, which detects space and shift-space keypresses, prevents default scroll behaviour, and programmatically scrolls half page.

Answer 3

I use vimium-C add-on on Firefox which has the following keyboard shortcuts:

d       scroll down half a page
u       scroll up half a page

(There are several other similar add-ons which you might want to look into and choose the one that fits best to your needs, including the original Vimium)