fix for bug in current Chrome 33 releases

Chrome 33 is incapable of getting the content of the body:after element if it has style "display: none;" (http://code.google.com/p/chromium/issues/detail?id=345653, http://code.google.com/p/chromium/issues/detail?id=341120). The workaround uses CSS visibility and moves the element out of the way.

Tested with Chrome 33.01750.146, Firefox 27.0.1 and IE 11.0.9600.16518.