js只弹出一次窗口的实例代码

<script type="text/javascript">
/**
* 实现只弹出一次窗口
* by www.jb200.com
*/
    var returnvalue = "";
    function openpopup(){
        <s:if test="isAlreadyGetGift == 0">
        $.colorbox({inline:true, href:'#getGiftForm',innerWidth:'650px;',innerHeight:'475px;',onOpen:true});
        $("#getGiftSuccess").hide();
        </s:if>
    }
function get_cookie(Name) {
   var search = Name + "=";
   if (document.cookie.length > 0) {
     offset = document.cookie.indexOf(search);
     if (offset != -1) {
         // if cookie exists
        offset += search.length;
         // set index of beginning of value
        end = document.cookie.indexOf(";", offset);
         // set index of end of cookie value
        if (end == 10){
               end = document.cookie.length;
               returnvalue=unescape(document.cookie.substring(offset, end));
               }
      }
   }
   return returnvalue;
}
function loadpopup(){
  if (get_cookie("popped")==""){
     openpopup();
   document.cookie="popped=yes"
    }
}
$(document).ready(function(){
        loadpopup();
});
</script>