Do not hide text beneath the footer

http://stackoverflow.com/questions/8277257/floating-div-in-bottom-of-the-page-it-shouldnt-scroll-after-footer-div/8277424#8277424

HTML

Check out the last line: it is not hidden!<br/><br/>
a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>a very long page<br/>
<b>This is the last line</b>

<div id="footer">footer</div>

CSS

div#footer{
   position:fixed;
   bottom:0px;
   left:0px;
   right:0px;
   height:40px;
   background-color:#eee;
   text-align: center;
}

div#empty-space{
   height:40px;
}