Animating position of top div creates space

[mr.kyky]

I have a div called #Wrap around my page content and have written the following function to shift everything up, so my Navigation at the top goes partially off page and my content has more screen space:\[code\]$('.NavShrink').click(function(up) { $('#Wrap').animate({ top: '-=130px'}); $(this).css('display', 'none'); $('.NavExpand').css('display', 'block');})\[/code\]I also have the following to bring it back down again:\[code\]$('.NavExpand').click(function(down) { $('#Wrap').animate({ top: "+=130px"}); $(this).css('display', 'none'); $('.NavShrink').css('display', 'block');})\[/code\]My problem at the moment is that the page seems to keep its full height when everything shifts up off screen, which creates 130px of blank space at the bottom of my content. Whats the way around this?my \[code\]#Wrap\[/code\] currently just has the style \[code\]position:relative;\[/code\] but have also tried with \[code\]height:100%;\[/code\] and \[code\]height:auto;\[/code\] with no luck.