Fade in doesn't work in IE

Fade in doesn't work in IE

I tried to use fade in the code below, it works in firefox but not ie7.

Does anyone know why? Thank you very much.


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<script src="jquery-1.4.2.min.js" type="application/javascript"></script>
<style type="text/css">
#layover{
background-color:#000;
filter:alpha(opacity=50);
opacity:0.5;
width:100%;
height:100%;
top:0px;
left:0px;
position:fixed;
z-index:100;
display:none;
}
#text{
color:#F00;
}


</style>
</head>

<body>
<div id="layover"></div>

dddddddddddddddddddddddd


<script language="javascript">
$("#text").click(function(){$("#layover").fadeIn(1000);});
</script>
</body>
</html>