Embedded in the first row of this table is a transparent image with a height
parameter set close to the expected height of the bar. When the page loads,
the resulting position of that image on the page is found and those
coordinates are used to position the navigation bar. View the
source for details.
The result is that the bar always appears over the table. Changing the page
content will not affect the relative placement as the image is contained in
the table and will move with it.
Note that the table is defined with a fixed width. The bar is defined with the
same width so that it will line up properly. You can
hide and
show the bar to see
the page underneath.