Basically I want to have a footer at the end of every page, flush to the
bottom of the browser window.
I can do this using a table layout by having a 100% high table, with a fixed
height (20px say) row at the bottom, and adding a background to that row.
When the content of the table is less than 100%, the table is still 100% and
thus the footer is at the bottom of the window.
However if I put a load of content in the table, it could stretch to say
200% and the footer is still at the very bottom of the page.