//retrieve value of a cookie
function get_cookie (c_name)
{ if (document.cookie.length > 0)
  { var c_start = document.cookie.indexOf(c_name + "=");
    if (c_start != -1)
    { c_start=c_start + c_name.length+1 ;
      var 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 ("");
}
function set_cookie (c_name, value)
{ var exdate=new Date();
  exdate.setDate(exdate.getDate()+1);
  document.cookie=c_name+ "=" +escape(value)+"; expires="+exdate.toGMTString();
}