JavaScript基础学习 页面显示倒计时效果

    
    
    
    Document

    
        div {
            margin: 200px;
        }
        
        span {
            display: inline-block;
            width: 40px;
            height: 40px;
            background-color: #333;
            font-size: 20px;
            color: #fff;
            text-align: center;
            line-height: 40px;
        }
    



    

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        var hours = document.querySelector('#hours');
        var minutes = document.querySelector('#minutes');
        var seconds = document.querySelector('#seconds');

        var nowTime = +new Date('2021-12-21 22:00:00');
        console.log(nowTime);

        //  开头就执行一次倒计时函数 为了在刷新时不显示页面空白而直接显示剩余时间
        getTimers();

        setInterval(getTimers, 1000);

        function getTimers() {
            var date = +new Date();
            var timeOut = (nowTime - date) / 1000;

            h = parseInt(timeOut / 60 / 60 % 24);
            h = h < 10 ? '0' + h : h;

            m = parseInt(timeOut / 60 % 60);
            m = m < 10 ? '0' + m : m;

            s = parseInt(timeOut % 60);
            s = s < 10 ? '0' + s : s;

            hours.innerHTML = h;
            minutes.innerHTML = m;
            seconds.innerHTML = s;
        }