<treerow xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" class="zebra"> <script xmlns="http://www.w3.org/1999/xhtml"><![CDATA[ function doe(){ document.getElementById('b').parentNode.removeChild(document.getElementById('b')); document.getElementById('c').parentNode.removeChild(document.getElementById('c')); } setTimeout(doe, 200); ]]></script> <box id="a"/> <mtr xmlns="http://www.w3.org/1998/Math/MathML"> <box xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" class="zebra" id="c"/> </mtr> <box style="display: inline;" id="b"/> <style xmlns="http://www.w3.org/1999/xhtml"> #a { counter-reset: chicken 11 egg; } #b { counter-increment: chicken -1 egg; } *[class=zebra] { counter-increment: chicken 5; } </style> </treerow>