<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <script> function boom() { var table = document.getElementById("table"); var doomed = document.getElementById("doomed"); doomed.parentNode.removeChild(doomed); var colgroup1 = document.createElement("colgroup"); table.appendChild(colgroup1); var thead = document.createElement("thead"); var tr = document.createElement("tr"); var td = document.createElement("td"); td.setAttribute("colspan", 0); tr.appendChild(td); thead.appendChild(tr); table.insertBefore(thead, colgroup1); colgroup1.parentNode.removeChild(colgroup1); var colgroup2 = document.createElement("colgroup"); table.appendChild(colgroup2); } </script> </head> <body onload="boom();"> <table id="table"><tbody><tr id="doomed"><td>x</tr></tbody></table> </body> </html>