The example your site gives for TFOOT places TFOOT after TBODY. As can be seen in the HTML 4.01 specification, this is not correct:
QUOTE
TFOOT must appear before TBODY within a TABLE definition so that user agents can render the foot before receiving all of the (potentially numerous) rows of data.

I think it would be good if this was corrected to place the TFOOT between the THEAD and TBODY elements. Especially since this is the example specifically for TFOOT...