Jquery 在ie上动画不显示。

Jquery 在ie上动画不显示。在火狐上却能显示出来。代码是这样的。
---------------------------------------
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<link type="text/css" rel="stylesheet" href="CSS/index.css" />
<link type="text/css" rel="stylesheet" href="CSS/table.css" />
<script type="text/javascript" src="js/calendar/WdatePicker.js"></script>
<script type="text/javascript" src="js/jquery-1.4.2.min.js"></script>
<script type="text/javascript" src="js/input_text.js"></script>
<script type="text/javascript" src="js/jquery.validate.js"></script>
<script type="text/javascript" src="js/jquery.metadata.js"></script>
<script language="javascript">function show(){
$("#trid").toggle('slow');
}
</script>
</head>
<body>
<div onclick="show()">sfsdfdf</div>
<table  width="600px"  bgcolor="gray" >
<tr id="trid">
<td> <table >
  <tr>
   <td>sfsdffffffffffffffffffffffffffffffffff
fffffffffffffffffffffffffffffffffffffffff</td>
   <td>sfsdffffffffffffffffffffffffffffffffff
fffffffffffffffffffffffffffffffffffffffff</td>
  </tr>
  <tr>
   <td>sfsdfffffffffffffffffffffffffffffffffffff
ffffffffffffffffffffffffffffffffffffff</td>
   <td>sfsdffffffffffffffffffffffffffffffffffff
fffffffffffffffffffffffffffffffffffffff</td>
  </tr>
  <tr> <td>sfsdfffffffffffffffffffffffffffffffffffff
ffffffffffffffffffffffffffffffffffffff</td>
   <td>sfsdffffffffffffffffffffffffffffffffffff
fffffffffffffffffffffffffffffffffffffff</td>
  </tr> 
</table>
</td>
</tr>
</table>
</body>
</html>
-------------------------------------------------------我发现JQUERY 只要显示或是隐藏 必须是最外层的独立的标签
才可以出现动画
比如说上面代码  想隐藏TABLE 里面的tr 就不能出现动画页面。却能隐藏，这是为什么啊。