js获取cookie过期时间

function getCookieExpiration(cookieName) {
    const cookies = document.cookie.split(';');
    for (let i = 0; i < cookies.length; i++) {
        let cookie = cookies[i].trim();
        if (cookie.startsWith(cookieName + '=')) {
            let cookieParts = cookie.split('=');
            let cookieValue = decodeURIComponent(cookieParts[1]);
            let expiresMatch = cookieValue.match(/expires=([^;]+)/i);
            if (expiresMatch) {
                return new Date(expiresMatch[1]).toISOString();
            }
            let maxAgeMatch = cookieValue.match(/max-age=([^;]+)/i);
            if (maxAgeMatch) {
                let maxAge = parseInt(maxAgeMatch[1], 10);
                let expires = new Date();
                expires.setSeconds(expires.getSeconds() + maxAge);
                return expires.toISOString();
            }
        }
    }
    return null; // 如果没有找到指定的Cookie或过期时间字段
}

// 使用示例
let expiresTime = getCookieExpiration('myCookie');
console.log('Cookie expires at:', expiresTime);