Затъмняване на Дисплея както при alert

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <title></title>
 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
 <style type="text/css">
 html, body {
 margin:0;
 padding:0;
 background:#FFF;
 color:#000;
 font-family:Verdana, Arial, Helvetica, sans-serif;
 font-size:0.85em;
 height:100%;
 }
 #myStyle {
 position:absolute;
 top: 0;
 left: 0;
 z-index:1;
 width:100%;
 height: 1000px;
 background-color: #000;
 filter:alpha(opacity=60);
 opacity: 0.6;
 display:none;
 }
 #myStyle a.close {
 float:right;
 position:relative;
 filter:alpha(opacity=100);
 opacity:1.0;
 margin-right:3px;
 display:inline;
 }
 </style>

 </head>
 <body>
 <div id="myStyle"><a href="#" class="close" onclick="document.getElementById('myStyle').style.display = 'none';return false">Close Me</a></div>
 <a href="#" onclick="document.getElementById('myStyle').style.display = 'block';return false">Darken Page</a>
 </body>
 </html>