<!doctype html>
<html>

Will be green if relative positioning stacking is supported:

<table border=0 cellpadding=0 cellspacing=0>
<tr><td style="position:relative; width:100px;"><div style="height:0px"><div style="height:100px;width:100px;background-color:green"></div></div>
<tr><td style="width:100px;height:100px;background-color:red">
</table>