<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <style>
div {width: 50px; height: 50px;}
</style>
 </head>
 <body>
 <table border="1"><tr><th><div/></th></tr></table>
 </body>
</html>