User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 If you insert a form usng javascript and said form contains a table containing a td which contains another form you get the table row ending as well as the nested form disappearing in the DOM, this only seems to happen on the first nested form. Reproducible: Always Steps to Reproduce: You can replicate using the js below. Note this only seems to happen when using js, if the html is inserted directly its all OK. html = '<form><table border="1"><tr><td>1<form></form></td><td>2</td></tr><tr><td>3<form></form></td><td>4</td></tr></table></form>';document.getElementById("<yourelementhere>").innerHTML = html; Actual Results: I got a wierd table, its almost as if the browser wrote a </tr> instead of the form. Expected Results: I expected my table to be OK

Thanks for the report! I can reproduce on trunk, but this works fine with the HTML5 parser <http://hsivonen.iki.fi/test-html5-parsing/>

Presumably the HTML5 parser does fixups similar to those for normal parsing during innerHTML sets.... But note that the markup in this case is invalid and is NOT implemented interoperably in browsers in general. Simple cases will work. Complicated stuff will break in nasty ways (non-tree DOM in IE, that sort of thing). Don't do it.

Marking FIXED per comment 2.