опять же
1.html:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<title>title</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<table style="display: none;"><tr><td>1</td></tr></table>
<iframe src="2.html"></iframe>
</body>
</html>
2.html:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<title>title</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript" src="jquery-1.3.2.js"></script>
<script type="text/javascript">
$(function() {
$('a').click(function() {
$('table', parent.document).show();
return false;
});
});
</script>
</head>
<body>
<a href="#">link</a>
</body>
</html>
у меня в ff работает