如何获取cookie的过期时间

function getCookieExpiration(cookieName) {
  var name = cookieName + "=";
  var decodedCookie = decodeURIComponent(document.cookie);
  var cookieArray = decodedCookie.split(';');
  
  for(var i = 0; i< cookieArray.length; i++) {
    var cookie = cookieArray[i].trim();
    
    if (cookie.indexOf(name) == 0) {
      var expiration = cookie.substring(name.length, cookie.length);
      return new Date(expiration);
    }
  }
  return null;
}

var expiration = getCookieExpiration("myCookie");
if (expiration) {
  console.log("Cookie过期时间: " + expiration);
} else {
  console.log("未找到名为myCookie的Cookie");
}