<html> <head> <title></title> <script type="text/javascript"> function toggle(b) { var adv = document.getElementById("it_guru"); var ns = 'none'; if (b) { ns= "table-row"; } adv.style.display = ns; } function boom() { toggle(true); document.documentElement.offsetHeight; toggle(false); document.documentElement.offsetHeight; toggle(true); document.documentElement.offsetHeight; toggle(false); document.documentElement.offsetHeight; } </script></head><body onload="boom();"> <form action="http://localhost/"> <table> <tbody> <tr> <td>Without the <tbody> tags Mozilla doesn't crash </td> </tr> </tbody> <tr id="it_guru"> <td>I disappear </td> </tr> <tr> <td>Without this row Mozilla doesn't crash </td> </tr> </table> </form> </body> </html>