popup che blocca la pagina .. quasi completato mi date un aiuto?

[limpido]

Ciao a tutti volevo creare una popup che esce appena viene caricata la pagina è fa un controllo se sei iscritto a facebook, se sei iscritto ti fa accedere caso contrario ti blocca per X secondi... se non clicci mi piace

l'unica cosa che non riesco a fare e di "ofuscare con un grigio chiaro la pagina che circonda il popup...
gli date un occhiata al codice ?

<!-- Inizio popup -->
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.js"></script>

<style type='text/css'>
#makingdifferentpopup{
position: fixed;
top:100px;
z-index:9999;
display:none;
padding:0px;
right:600px;
border:10px solid rgba(82, 82, 82, 0.7);
-webkit-background-clip: padding-box; /* for Safari */
background-clip: padding-box; /* for IE9+, Firefox 4+, Opera, Chrome */
-webkit-border-radius:8px 8px 8px 8px;
-moz-border-radius:8px 8px 8px 8px;
border-radius:8px 8px 8px 8px;
width:400px;
height:360px;
overflow:hidden;
}
#makingdifferentpopup span{
font-size:20px !important;
font-weight:bold !important;
}
#makingdifferentpopup h1{
background:#6d84b4 url(http://4.bp.blogspot.com/-rNUTIpDQ21s/T0NqE_vv6GI/AAAAAAAACps/GSoWE2n9Oy8/s1600/%255Bwww.gj37765.blogspot.com%255Dh1.png) 98% no-repeat;
border:1px solid #3b5998 !important;
color:#FFFFFF !important;
font-size:20px !important;
font-weight:700 !important;
padding:5px !important;
margin:0 !important;
font-family:"lucida grande",tahoma,verdana,arial,sans-serif !important;
overflow:hidden !important;
}
.htmlarea{
font-size:12px !important;
font-weight:normal !important;
height:265px !important;
padding:1px !important;
background:#fff !important;
border-bottom:2px solid #ddd;
overflow:hidden !important;
}
#mdfooter{
text-align:left;
background:#F2F2F2 !important;
height:56px !important;
padding:10px 10px 10px 10px !important;
overflow:hidden !important;
}
#mdclose{
float:right;
background-color:#eee !important;
border:1px solid #ccc !important;
color:#111 !important;
font-weight:bold !important;
padding:5px 8px 5px 8px !important;
text-decoration:none !important;
display:inline-block !important;
font-family:"lucida grande",tahoma,verdana,arial,sans-serif !important;
outline:none !important;
position:relative !important;
font-size:18px !important;
margin:1px !important;
}
#mdclose:active{
top:1px;
left:1px;
}
.grabthis{
bottom:80px;
font:8px "lucida grande",tahoma,verdana,arial,sans-serif;
position:absolute;
right:6px;
text-align:right;
z-index: 99999;
}
.grabthis a{
color: #000;
text-decoration:none;
}
.grabthis a:hover{
text-decoration:underline;
}
</style>
<script type='text/javascript'>
jQuery(document).ready(function() {
function makingdifferent_ppopup()  {var sec = 10
var timer = setInterval(function() {
   $("#mdfooter span").text(sec--);
   if (sec == 0) {
      $("#makingdifferentpopup").fadeOut("slow");
      clearInterval(timer);
   }
},1000);
  var mdwh = jQuery(window).height();
  var mdpph = jQuery("#makingdifferentpopup").height();
  var mdfromTop = jQuery(window).scrollTop()+50;
 jQuery("#makingdifferentpopup").css({"top":mdfromTop});}
jQuery(window).fadeIn(makingdifferent_ppopup)
.resize(makingdifferent_ppopup)
 //alert(jQuery.cookie('sreqshown'));
 //var mdww = jQuery(window).width();
 //var mdppw = jQuery("#makingdifferentpopup").width();
 //var mdleftm = (mdww-mdppw)/2;
   var mdleftm = 500;
 //var mdwh = jQuery(window).height();
 //var mdpph = jQuery("#makingdifferentpopup").height();
 //var mdfromTop = (jQuery(window).scrollTop()+mdwh-mdpph) / 2;
 jQuery("#makingdifferentpopup").animate({opacity: "1", left: "0" , left:  mdleftm}, 0).show();
     jQuery("#mdclose").click(function() {
jQuery("#makingdifferentpopup").animate({opacity: "0", left: "-5000000"}, 1000).show();});});
</script>
<div id="makingdifferentpopup" style="width: 497px; height: 373px">
<h1 align="center">Clicca su mi piace e accedi al sondaggio</h1>
<div class="htmlarea" style="width: 487px; height: 265px">
<iframe src="//www.facebook.com/plugins/likebox.php?href=https://www.facebook.com/pages/wwwcittadimercatosanseverinoit-Mercato-San-Severino-SA/117628394937568&amp;width=400&amp;colorscheme=light&amp;show_faces=true&amp;border_color=%23fff&amp;stream=false&amp;header=false&amp;height=250" scrolling="no" frameborder="0" style="border:medium none; overflow:hidden; width:483px; height:250px" allowtransparency="true"></iframe>
<div class="grabthis">
</div>
</div>
<div id="mdfooter" style="width: 488px; height: 36px">Per accedere clicca mi 
	piace oppure attendi...<span> 180</span> secondi.</div>
</div>
<!-- End popup -->

 

[criric]

Ciao, se non hai già risolto prova a guardare il sorgente di questo semplice esempio