How can I make the Page Up and Page Down keys scroll a full screenful in browsers?

For as long as I can remember I have been frustrated by the browser behavior whereby using the Page Up and Page Down keys on the keyboard doesn't scroll the web page by a full screenful. Whenever I am reading a long web page, I prefer to read the whole screen from top to bottom, press Page Down, then continue reading at the top of the next page. However, doing this always leaves a few lines of the previous screen at the top of the next screen. Often this completely breaks my concentration as I search through the first few lines of the screen to remember exactly which line I previously left off reading on the previous screen. Simply rereading the first few lines again each time has a similar effect on my concentration.

Is there any way to change this behavior so that the Page Up and Page Down keys scroll 100% of the current screen instead of leaving a few lines of the previous page at the top of the screen after a "full page" scroll? This "partial page scrolling" behavior seems to be the normal behavior on current versions of IE, Chrome, Firefox, and Safari, though by differing amounts (IE and Chrome both leave about five lines from the previous screen, while Firefox and Safari only leave one or two).

For example, here is a screen in IE9 before using the Page Down key:

And here is the next screenful after using the Page Down key (the "duplicated" lines are circled in red):

I just tested this in Firefox 19 on the main questions list, and there is only a little bit of overlap between screens. I suppose this is there so that in case a line of text is split between screens it is readable on the second one.

Screen 1:

Screen 2:

This overlap appears to be a fixed amount rather than determined by the font size, so sometimes, such as this example, there is more overlap that necessary. However, with large print you might need that much overlap to avoid cutting a line in half on both screens.

For a couple of reasons:

1. Allows for overlap in reading in cases where a line might be split or cramped at the bottom.

2. Users tend to page down before reading the last few lines. So then they have to scroll back up a few lines. This saves them that effort.

NOTE: This is the same if you set your mouse wheel to scroll one screen at a time or use the Page buttons.

Also it's not just browsers that do this Word and Notepad++ do this as well but limit it to the last line rather than a few lines.