Code popup thông báo xuất hiện chỉ 1 lần khi vào trang web blogspot

<style >
.modal-bg {
position: fixed;
height: 100%;
width: 100%;
background: rgba(0,0,0,.8);
z-index: 999;
display: none;
top: 0;
left: 0;
}
.modal {
visibility: hidden;
text-align:center;
top: -400px; 
left: 40%;
margin-left: -250px;
width: 690px;
background: url(modal-gloss.png) no-repeat -200px -80px;
position: absolute;
z-index: 9999;
padding: 30px 40px 34px;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
border-radius: 5px;
-moz-box-shadow: 0 0 10px rgba(0,0,0,.4);
-webkit-box-shadow: 0 0 10px rgba(0,0,0,.4);
-box-shadow: 0 0 10px rgba(0,0,0,.4);
}

.modal.small { width: 200px; margin-left: -140px;}
.modal.medium { width: 400px; margin-left: -240px;}
.modal.large { width: 600px; margin-left: -340px;}
.modal.xlarge { width: 800px; margin-left: -440px;}

.modal .close-modal {
font-size: 42px;
line-height: .5;
position: absolute;
top: 24px;
right: 33px;
color: red;
text-shadow: 0 -1px 1px rbga(0,0,0,.6);
font-weight: bold;
cursor: pointer;
}
.big-link { display:block; margin-top: 100px; text-align: center; font-size: 70px; color: #06f; }
</style>
  <!-- <script type="text/javascript" src="jquery-1.4.4.min.js"></script> -->
  <script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.js"></script>
  <script type="text/javascript" src="https://seovnpro.googlecode.com/files/popup.js"></script>


<script type="text/javascript" >
    jQuery.noConflict();      /* dòng chống conflict jquery */
    jQuery(window).load(function() {
        if(document.cookie.indexOf("adf") == -1) /*  Bỏ dòng này thì nó hiện thông báo liên tục mỗi khi mở web lên rất là phiền  */
        {
            document.cookie = "popunder1=adf";
            jQuery('#myModal').bittuotblog(jQuery('#myModal').data());
        }
    });
</script>
<div id="myModal" class="modal">
   <img src="http://hyundaihillstate.com.vn/wp-content/uploads/2014/03/Untitled.png" />
   <a class="close-modal">X</a>
</div>