<html>
<head>
<script language="javascript">
function overlay() {
xyz = document.getElementById("overlay");
xyz.style.visibility = (xyz.style.visibility == "visible") ? "hidden" : "visible";
}
</script>
<style type="text/css">
#overlay {
visibility: hidden;
position: absolute;
left: 0px;
top: 0px;
width:100%;
height:100%;
text-align:center;
z-index: 1000;
background-color:gray;
opacity: 0.8; /*FireFox*/
filter:alpha(opacity=80); /*IE*/
-moz-opacity: 0.8;
}
#overlay div {
width:300px;
margin: 100px auto;
background-color: #fff;
border:1px solid #000;
padding:15px;
text-align:center;
}
}
</style>
</head>
<body>
<div id="overlay">
<div>
Click here to [<a href='#' onclick='overlay()'>close</a>]
<p>Content</p>
<p><input type="button" value="Submit" /></p>
</div>
</div>
<input type='button' value='show modal dialog' onclick='overlay()' />
</body>
</html>