function get_cookie(cn) {
   get_data = document.cookie;
   cv = new Array();
   gd = get_data.split(";");
   for (i in gd) {
	  a = gd[i].split("=");
	  a[0] = a[0].replace(" ","");
	  cv[a[0]] = a[1];
   }
   if (cv[cn]) return unescape(cv[cn]);
   else return "";
}
function set_cookie(cn,val) {
   ex = new Date();
   ex = new Date(ex.getTime() + (1000 * 60 * 60 * 24 * days));
   y = ex.getYear(); if (y < 1900) y += 1900;
   hms = ex.getHours() + ":" + ex.getMinutes() + ":" + ex.getSeconds();
   p = String(ex).split(" ");
   ex = p[0] + ", " + p[2] + "-" + p[1] + "-" + y + " " + hms + " GMT;";
   document.cookie = cn + "=" + escape(val) +"; expires=" + ex;
}
// クッキーの有効日数
days = 30;