CORRECTION: no, "rowspan" doesn't work in IE, which ONLY understands
it with a capital S: rowSpan. So, now (since 1.2.5) the only way to
remove a rowspan in IE is to do
.attr('rowSpan',1)
and not removeAttr('rowspan') or removeAttr('rowSpan') or
attr('rowspan',1).
FF forgives and understands all of the above. Weird...