Get page height?

Hi, I was wondering if it would be possible to get the page height using php? The reason I would like to do this is so that I can include a link to the top of the page if the page is long enough, but not to display it for very short pages (where it would not be needed:) Cheers for your help, Donald ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Accessible Computers, competitive prices on all computer related items including Hardware, Software, Consumables and Custom Built PCs http://www.AccessibleComputers.co.uk ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ personal website: http://www.donaldrnoble.f2s.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~