Extra padding below footer when using html5 doctype

I have recently applied a html5 doctype to this page: http://www.hostbasket.com/nl/shared-webhosting/windows/pakketten.html Now I notice extra padding below the footer. The two footer divs are positioned absolute to prevent the white background from appearing when pages are not 100% of height. Everything is fine with a transitional xhmtl1 doctype.

Using Firebug, I've set the #footer_bottom to bottom:-17px; the white space disappears. But why 17px? And 开发者_开发技巧I don't like negative position absolute!