Hallo Marko!
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<title></title>
<style type="text/css">
body, html {height:100%;}
table.hundert {height:100%;width:100%}
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<table class="hundert">
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<table valign=top style="height:10">oberer kram</table>
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<tr><td valign=middle style="height:100%">
hier die 100% weg !!!!!
<table class="hundert" valign=middle>unterer, die hier 100% hoch</table>
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</table>
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