how use rows[] in IE8

[h2ovn]

Collection of tr objects (rows) in a table can;t use in IE8.

var oTable = document.getElementById("tbl");
for (var i = 0; i < oTable.rows.length; i++)
{
	oTable.rows[i].style.fontWeight = "bold";
}

run with IE 7,6 or firefox ok. but run with IE8 has error rows is null.
help me. I need use rows. How ?

[Dormilich]

if this is not triggered by an event you could even use simple CSS
[CODE=css]#tbl {
font-weight: bold; }
/* tr and td will inherit that value */[/CODE]