<html xmlns="http://www.w3.org/1999/xhtml" class="reftest-wait"> <head> <script> function boom() { var tr2 = document.getElementById('tr2'); var newTD = document.createElement('td'); newTD.setAttribute('colspan', 2); newTD.appendChild(document.createTextNode('x')); tr2.insertBefore(newTD, document.getElementById('b')); document.getElementById('a').setAttribute('colspan', 1); document.getElementById('b').setAttribute('colspan', 3); document.documentElement.removeAttribute("class"); } </script> </head> <body onload="setTimeout(boom, 250);"> <table style="border-collapse: collapse;" border="1"> <tbody> <tr> <td id="a" colspan="3">A</td> </tr> <tr id="tr2"> <td id="b">B</td> </tr> <tr> <td>C</td> </tr> </tbody> </table> </body> </html>