function getCookieValue (cookieName) {
  var exp = new RegExp (escape(cookieName) + "=([^;]+)");
  if (exp.test (document.cookie + ";")) {
    exp.exec (document.cookie + ";");
    return unescape(RegExp.$1);
  }
  else return false;
}



function writePersistentCookie (CookieName, CookieValue, periodType, offset) {

  var expireDate = new Date ();
  offset = offset / 1;
  
  var myPeriodType = periodType;
  switch (myPeriodType.toLowerCase()) {
    case "years": 
     var year = expireDate.getYear();     

     if (year < 1000) year = year + 1900;     
     expireDate.setYear(year + offset);
     break;
    case "months":
      expireDate.setMonth(expireDate.getMonth() + offset);
      break;
    case "days":
      expireDate.setDate(expireDate.getDate() + offset);
      break;
    case "hours":
      expireDate.setHours(expireDate.getHours() + offset);
      break;
    case "minutes":
      expireDate.setMinutes(expireDate.getMinutes() + offset);
      break;
    default:
      alert ("Invalid periodType parameter for writePersistentCookie()");
      break;
  } 
  
  document.cookie = escape(CookieName ) + "=" + escape(CookieValue) + "; expires=" + expireDate.toGMTString() + "; path=/";
}  

 

function deleteCookie (cookieName) {

  if (getCookieValue (cookieName)) writePersistentCookie (cookieName,"Pending delete","years", -1);  
  return true;     
}