操作cookie

$.extend($, {
     setCookie: function(c_name, value, expiredays) {
          var exdate = new Date();
          exdate.setDate(exdate.getDate() + expiredays);
          document.cookie = c_name + "=" + escape(value) + ((expiredays === undefined) ? "" : ";expires=" + exdate.toGMTString());
     },
     getCookie: function(c_name) {
          if (document.cookie.length > 0) {
               c_start = document.cookie.indexOf(c_name + "=");
               if (c_start != -1) {
                    c_start = c_start + c_name.length + 1;
                    c_end = document.cookie.indexOf(";", c_start);
                    if (c_end == -1) c_end = document.cookie.length;
                    return unescape(document.cookie.substring(c_start, c_end));
               }
          }
          return "";
     }
});