js倒计时3小时的代码

// 获取当前时间
let now = new Date();

// 设置目标时间（当前时间加上3小时）
let targetTime = new Date(now.getTime() + 3 * 60 * 60 * 1000);

// 更新倒计时显示的函数
function updateCountdown() {
    let currentTime = new Date();
    let remainingTime = targetTime - currentTime;

    if (remainingTime <= 0) {
        clearInterval(intervalId); // 倒计时结束，清除定时器
        console.log('倒计时结束');
        return;
    }

    let hours = Math.floor(remainingTime / (1000 * 60 * 60));
    let minutes = Math.floor((remainingTime % (1000 * 60 * 60)) / (1000 * 60));
    let seconds = Math.floor((remainingTime % (1000 * 60)) / 1000);

    console.log(`${hours}小时 ${minutes}分钟 ${seconds}秒`);
}

// 每秒更新一次倒计时显示
let intervalId = setInterval(updateCountdown, 1000);

// 立即更新一次显示
updateCountdown();

// 保存开始时间到localStorage
localStorage.setItem('countdownStartTime', new Date().getTime());

// 页面加载时从localStorage读取开始时间
let startTime = localStorage.getItem('countdownStartTime');
let targetTime = new Date(parseInt(startTime) + 3 * 60 * 60 * 1000);

// 其余代码保持不变

function updateCountdown() {
    let currentTime = new Date();
    let remainingTime = targetTime - currentTime;

    if (remainingTime <= 0) {
        clearInterval(intervalId);
        console.log('倒计时结束');
        // 倒计时结束后的操作，例如跳转页面
        window.location.href = 'https://example.com';
        return;
    }

    // 其余代码保持不变
}