Cookie + popup

<div class="modal" id="popup" style="display:none">
        <div class="modal-dialog">
            <div class="modal-content">
              <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
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              </div>
            </div>
          </div>
      </div>
 
    <div id="popup_bg" class="modal-backdrop fade in"  style="display:none"></div>

 $(document).ready(function (){
 
            function createCookie(name,value,days) {
                if (days) {
                    var date = new Date();
                    date.setTime(date.getTime()+(days*24*60*60*1000));
                    var expires = "; expires="+date.toGMTString();
                }
                else var expires = "";
                    document.cookie = name+"="+value+expires+"; path=/";
                }
            function getCookie(name) {
                var dc = document.cookie;
                var prefix = name + "=";
                var begin = dc.indexOf("; " + prefix);
                if (begin == -1) {
                    begin = dc.indexOf(prefix);
                    if (begin != 0) return null;
                }
                else
                {
                    begin += 2;
                    var end = document.cookie.indexOf(";", begin);
                    if (end == -1) {
                    end = dc.length;
                    }
                }
                return unescape(dc.substring(begin + prefix.length, end));
            }
 
            var myCookie = getCookie("popup");
 
            if (myCookie == null) {
                $("#popup").show();
                $("#popup_bg").show();
            }else{
                $("#popup").hide();
                $("#popup_bg").hide();
            }
 
 
 
            $("#popup .close").click(function(){
                $("#popup").slideUp();
                $("#popup_bg").hide();
                createCookie('popup','popup',7)
            });
        });