JS: lineHeight

[krok]

Hi,
how i can find height of row:
in HTML is
<TABLE id=&quot;myTable&quot;>
<COLGROUP width=&quot;50&quot;>
<COLGROUP width=&quot;0*&quot;>
<TR><TD>zzzzzz yyyyyyyy

http://wwwwwwww

tttt - this is longer than 50 and this cell will be wrapped</TD><TD>blabla</TD></TR></TABLE>

and I'd like to know the height of wrapped cell,
I test (i means index of row or TR in table)document.all.myTable.rows.style.lineHeight or
document.all.myTable.all.tags(&quot;TR&quot.style.lineHeight, but these return &quot;&quot;

What's the way to do it?
Thanx