onload iframe event

the below code:

function yt_do_upload()
{
//were go confirm the status? in nexturl
$('form').action = $('url').value + "?nexturl=http://cesar.la/";
$('form').submit();
$('yt_frame').onload = yt_done;
$('loading').innerHTML = "Uploading to youtube!...";
setTimeout("ashow('loading');",3000);
}

calls this function:

function yt_done()
{
alert("Upload done!");
ahide("loading");
}

but in IE nothing happens... is there anyway to fix this?