function createCookie(name, value, days) {
  var date, expires;
  if (days) {
    date = new Date();
    date.setTime(date.getTime() + (days*24*60*60*1000));
    expires = "; expires=" + date.toGMTString();
  }
  else {
    expires = "";
  }
  document.cookie = name + "=" + value + expires + "; path=/";
}

function getCookie(name) {
  var nameEQ = name + "=",
      ca = document.cookie.split(';'),
	  i, c;

  for(i = 0; i < ca.length; i += 1) {
      c = ca[i];
      while (c.charAt(0) == ' ') {
        c = c.substring(1,c.length);
	  }
      if (c.indexOf(nameEQ) == 0) {
        return c.substring(nameEQ.length, c.length);
	  }
  }
  return null;
}

function eraseCookie(name) {
  createCookie(name, "", -1);
}