A website I've been working on has a black bar across the bottom. Under some conditions, however, there is a gap between the bar and the bottom of the page -- white for the body. The conditions vary between browsers and OSes. To keep things simple, I'll describe what happens with my principle development environment -- Chrome under Ubuntu.
The main body of the website is fixed width, centered against a neutral background. If the browser window is narrowed so that a horizontal scrollbar appears, the gap appears.
I have tried various things to find the gap so I can move the bar down or whatever but nothing seems to work. I tried using the document height but I found that it is greater than the actual display area which probably means that it is including something not visible (which is fine) but how do I reliably determine the extra? Or is there another solution I should be looking at (I won't bother listing all that I have tried)?
Thanks