Add Facebook Popup Widget To Blogger

1. Go to your blogger dashboard >> Layout.
2. Click on Add a Gadget >> select HTML/JavaScript from list
Copy The below code and Replace facebook.com/theinternetsurfer with your facebook username, save and you are done

<script src='http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js' type='text/javascript'></script>

<style>
#tisback {
display:none;
background:rgba(0,0,0,0.8);
width:100%;
height:100%;
position:fixed;
top:0;
left:0;
z-index:99999;
}
#tis-exit {
width:100%;
height:100%;
}
#tisbox {
background:white;
width:420px;
height:270px;
position:absolute;
top:58%;
left:63%;
margin:-220px 0 0 -375px;
-webkit-box-shadow: inset 0 0 50px 0 #939393;
-moz-box-shadow: inset 0 0 50px 0 #939393;
box-shadow: inset 0 0 50px 0 #939393;
-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 5px;
margin: -220px 0 0 -375px;
}
#tisclose {
float:right;
cursor:pointer;
background:url(http://3.bp.blogspot.com/-NRmqfyLwBHY/T4nwHOrPSzI/AAAAAAAAAdQ/8b9O7O1q3c8/s1600/tisclose.png) repeat;
height:15px;
padding:20px;
position:relative;
padding-right:40px;
margin-top:-20px;
margin-right:-22px;
}
.remove-borda {
height:1px;
width:366px;
margin:0 auto;
background:#F3F3F3;
margin-top:16px;
position:relative;
margin-left:20px;
}
#linkit a.visited,#linkit a,#linkit a:hover {
color:#80808B;
font-size:10px;
margin: 0 auto 5px auto;
float:center;
}
</style>

<script type='text/javascript'>
//<![CDATA[
jQuery.cookie = function (key, value, options) {
// key and at least value given, set cookie...
if (arguments.length > 1 && String(value) !== "[object Object]") {
options = jQuery.extend({}, options);
if (value === null || value === undefined) {
options.expires = -1;
}
if (typeof options.expires === 'number') {
var days = options.expires, t = options.expires = new Date();
t.setDate(t.getDate() + days);
}
value = String(value);
return (document.cookie = [
encodeURIComponent(key), '=',
options.raw ? value : encodeURIComponent(value),
options.expires ? '; expires=' + options.expires.toUTCString() : '', // use expires attribute, max-age is not supported by IE
options.path ? '; path=' + options.path : '',
options.domain ? '; domain=' + options.domain : '',
options.secure ? '; secure' : ''
].join(''));
}
// key and possibly options given, get cookie...
options = value || {};
var result, decode = options.raw ? function (s) { return s; } : decodeURIComponent;
return (result = new RegExp('(?:^|; )' + encodeURIComponent(key) + '=([^;]*)').exec(document.cookie)) ? decode(result[1]) : null;
};
//]]>
</script>
<script type='text/javascript'>
jQuery(document).ready(function($){
if($.cookie('popup_user_login') != 'yes'){
$('#tisback').delay(100).fadeIn('medium');
$('#tisclose, #tis-exit').click(function(){
$('#tisback').stop().fadeOut('medium');
});
}
$.cookie('popup_user_login', 'yes', { path: '/', expires: 7 });
});
</script>
<div id='tisback'>
<div id='tis-exit'>
</div>
<div id='tisbox'>
<div id='tisclose'>
</div>
<div class='remove-borda'>
</div>
<iframe allowtransparency='true' frameborder='0' scrolling='no' src='//www.facebook.com/plugins/likebox.php?
href=http://www.facebook.com/theinternetsurfer&width=402&height=255&colorscheme=light&show_faces=true&show_border=false&stream=false&header=false'
style='border: none; overflow: hidden; margin-top: -19px; width: 402px; height: 230px;'></iframe><center>
<span id="linkit"><a href="http://www.theinternetsurfer.blogspot.com">Facebook Popup Widget</a></span></center>
</div>
</div>

See Demo